Bulletin [Nos. 71-80 (Jan. 1930 - Feb. 1939)]

GEORGIA STATE BOARD
of ENTOMOLOGY

M . S. YEOMANS, State Entomologist

BULLETIN No. 71 _ g' ()

January, 1930 -

- /7-3 9

Peach Insects and Diseases

and How to Control Them

B y CHARLES H. ALDEN Entomologist

aNERAJ... UBRAR Y

ONlVERStTY OF GEORGI/ ~ r,F'nP r.'"'

STATE CAPITOL

ATLANTA, GA.

GEORGIA STATE BOARD OF ENTOMOLOGY
Organization and Staff HON. EUGENE TALMADGE, Commissioner of Agriculture, Atlanta. HON. A. MITCHELL METCA.LF,
Clarkesville.
HON. T. W. HOLLIS, Buena Vista.
M. S. YEOMANS, State Entomologist and Secretary of the Board, Atlanta
CHARLES H. ALDEN Entomologist, Cornelia.
J. B. GILL, Entomologist, Albany.
TOM O'NEILL Entomologist, Atlanta.
D. F. F ARLINGER, Assistant, Cornelia.
D. C. MOODY, Assistant, Cornelia. J. H. GIRARDEAU, Chief Inspector, McRae.
C. H. GADDIS, Inspector, Albany.
A. B. HAMLIN, Inspector, Macon.
J.D. FULLER, Inspector, Mountville.
JOHN F. MONROE, Inspector, Athens.
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TABLE OF CONTENTS

PAGE
1. Condensed Peach Pest Control Schedule__ ___________ 4

2. Important Peach Insects __ ___________________ ____ 5

(a) Plum Curculio ----------- ----- - ----------- 5

(b) Peach Tree Borer --------------- -- ---- - - -- 8

(c) Oriental Fruit Moth _________ ______________ 9

....

(d) San Jose Scale____________________________ 10

0 3. Important Peach Diseases __ ______ ______ ____ ______ 5

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(a) Brown Rot __________ _____________________ 13 (b) Peach Scab __________________ __ __ __ __ ___ __ 14

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(c) Leaf Curl --------------- -----------------14

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(d) Bacterial Spot _____________________ __ _____ 15 4. Phony Peach --------------------- -- ---- - -------16

)o. 5. Less Important Peach Insects and Diseases________ ___ 17

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(a) Shot Hole Borer_ _________ _________________ 17 (b) Lesser Peach Borer_________ _______________ 17 (c) Peach Twig Borer_________________________ 17

...

(d) Corn Ear Worm ___________ _________ _____ _17

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(e) Grasshoppers _____ ___________________ _____ 18 (f) Crown Gall __________________ __________ __18

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(g) Rosette and Yellows _______ ____ ___ ______ ___ 18 (h) The Nematode Worm __ __ __________________ 18

11.1 6. Beneficial Insects and Diseases __ ____ ___ ____ ___ _____ 19 ::t 1- 7. Insecticides and Fungicides_______________________ 20

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8. Photographs -------------------------- - ------23-31

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CONDENSED PEACH PEST CONTROL SCHEDULE
Winter or Dormant Spraying
For control of San Jose scale: Spray when trees are thoroughly dormant, with either liquid concentrated lime sulfur one gallon to water eight gallons; or lubricating oil emulsion nine gallons to water 191 gallons. Trees incrusted with scale can be sprayed twice-once in December and once in early February, with either lime sulfur or oil emulsion.
For control of leaf curl: Spray when trees are dormant and before leaf and fruit buds have swelled, with either lime sulfur one gallon and water 15 gallons; or 4-4-50 Bordeaux mixture. The lime sulfur used for scale control will control leaf curl; or the 4-4-50 Bordeaux mixture can be combined with the oil emulsion as given for the San Jose scale to control this disease.
Summer Spray Schedule
For control of curculio, grasshoppers, brown rot and scab.
First application: When 75 % of the petals have fallen, spray with one pound of powdered lead arsenate and three pounds of stone, or four pounds of hydrated lime to 50 gallons of water.
Second application: When shucks are shedding exposing small peaches. Same materials as for first application (See Plate I).
Third application: Two weeks after the second application 8-8-50 self-boiled lime sulfur.
Fourth application: Four weeks before each variety is due to ripen; one pound of lead arsenate in an 8-8-50 selfboiled lime sulfur.
Summe,r Dust Schedule
Time of application the same as the spray schedule. First and second applications 0-5-95 dust. Third application 80-5-15 dust. Fourth application 80-5-15 dust.
Early varieties should receive the first, second and fourth applications as called for in the schedules. Tested proprietary compounds can be substituted for materials listed.
After Harvest Curculio Control
Dust with 90 o/o lime and 10% lead arsenate,. four weeks after harvest and again two weeks later.
[4]

Pa.radichlorobenzene Control of Peach Tree Borer
Time to apply-North Georgia, September 25-0ctober 5. Middle and South Georgia, October 10-20.
Treat four and five-year-old trees with a 3,4-ounce dose and expose for four weeks. Treat older trees with a oneounce dose and expose for six weeks. Trees from one to three years old must be wormed by hand.
PEACH INSECTS AND DISEASES AND HOW TO CONTROL THEM
Important Peach Insects
The four most important insects attacking peach trees are the plum curculio (Conotrachelus nenupha;r Hbst.), the peach tree borer (A egeria exitiosa Say), the Oriental fruit moth (Lasp eyresia molesta Busck) and the San Jose scale (Aspidiotus perniciosus Comst.) . The above-named account for more than ninety per cent of the losses from insects in the commercial and home orchards of the state.
Plum Curculio
This is the worst insect attacking both green and ripening peaches in the state. The adult is a small snout beetle that emerges in the spring at about blossoming time and first feeds on the blossoms and opening leaves. While the peaches are small the female inserts eggs into the flesh of the peach. A tiny worm or grub hatches from the egg and grows by feeding on the pulp, mostly around the seed (See Plate II). It causes the green peaches to fall and ruins many of the harvested peaches for shipping. There are one or two generations per year, depending on the season, and when there is a large second generation, many of the ripening peaches are stung resulting in a high percentage of wormy peaches at harvest.
Control. The spray and dust schedules given on pages 6 and 7 are the most important control measures. Supplementary measures that are necessary are jarring in the spring, picking up drops, cultivation, orchard sanitation, afterharvest dusting and the burning over of woodlands and other hibernating places in the winter.
Jarring should be done in the early morning from sun-up until eight or nine a. m., mostly on the rows adjacent to the woods and along the outside edges of the orchard. It should be started as soon as the beetles commence to leave the hibernating places in the spring which is about the blossoming time of the late varieties of peaches. The best method is to use two six-foot by twelve-foot jarring frames, over which is tacked unbleached sheeting with one frame
[5]

having a notch in the center of one of the twelve-foot sides

for the reception of the tree. Five laborers are required,

four to carry the frames and one with a ten-foot padded

pole to jar the main branches. The frames are placed

under the tree on the ground and the main branches jarred

sharply. About ten trees at a time can be thus jarred,

and then the beetles should be removed from the frames by

hand and dropped into a can of kerosene. Thousands of

beetles can be caught and destroyed in this manner, espe-

cially in the early spring following a year of heavy curculio

infestation at harvest.

Undoubtedly the most important supplementary control

measure is to pick up the drops. They should be picked

up at least three times, starting about one month after full

bloom with the following two collections five and ten days

later. All drops picked up should be immediately taken

from the orchard and buried two feet under ground. To

even leave a basket of drops over night in the orchard re-

sults in the escape of many grubs into the soil.

Cultivating the soil frequently beneath and close to the

tree from about the first of May until the last of June will

destroy many of the pupal cells in the soil. The larvae

pupate almost entirely in the top three inches of soil and

the ground should be broken to at least that depth.

After-harvest dusting will kill many beetles feeding in

the orchard before they go into hibernation. Two applica-

tions of lead arsenate-lime dust, consisting of 90 parts of

hydrated lime and 10 parts of lead arsenate, should be ap-

plied with a power duster, using about one-fifth of a pound

per tree per application. The first application should be

made four weeks after harvesting Elbertas and the second

one two weeks later.



As the adult curculios spend the winter in the woods and

similar cover around peach orchards, many can be killed

by burning over during a dry period in the winter. It is

only necessary to burn over the area lying within about

three hundred yards of the orchard. Care should be taken

not to burn an unnecessary area so as to avoid destroying

valuable undergrowth such as young forest trees.

Practice of sanitation such as cleaning up terrace and

fence rows and the removal of prunings and brush piles

will result in eliminating many hibernating places for the

beetles in the peach orchards.

Spray Schedule
First application: When 75 ro of the petals have fallen use one pound of powdered lead arsenate, and three pounds of stone lime to 50 gallons of water, for the control of curculio and grasshoppers.
[6]

Second application: When shucks are shedding exposing the small peaches, use same materials as on first application, for the control of curculio and grasshoppers.
Third application: Two weeks after second application. Use 8-8-50 self-boiled lime sulfur for the control of brown rot and scab.
Fourth application: Four weeks before each variety is due to ripen, use one pound of powdered lead arsenate in an 8-8-50 self-boiled lime sulfur formula for the control of curculio, brown rot and scab.
Dust Schedule
First application: When 75 % of the petals have fallen use lead arsenate 5%, hydrated lime 95 %, for control of curculio and grasshoppers.
Second application : When shucks are shedding exposing small peaches. Same as first application.
Third application: Two weeks after second application. Use dusting sulfur 80 %, lead arsenate 5%, hydrated lime 15%, for control of brown rot, scab and curculio.
Fourth application : Four weeks before each variety ripens. Same as third application.
General Instructions
The stone lime should be slacked by adding water slowly until all the lime is slacked and then more water added to make a liquid. Four pounds of hydrated lime may be used in place of the three pounds of stone lime.
Self-boiled lime sulfur is made as follows: Place eight pounds of stone lime in a 50-gallon barrel and add a little water to start slacking; then add eight pounds of sulfur. Add enough water to keep the mixture from getting dry. Boil for about five minutes, cool off with water, strain into tank and dilute to 50 gallons. The mixture should be cooled off when red streaks occur on top. The formula can be made in larger amounts, as 16-16-100 or 32-32-200. Tested proprietary compounds as directed by the manufacturers can be used as a substitute for self-boiled lime sulfur, if desired.
The early varieties need only three sprays as called for in the first, second and fourth applications. All varieties from the Carmen on, should receive four applications.
If brown rot is very prevalent, an 80-20 dust, consisting of 80 pounds of sulfur and 20 pounds of hydrated lime, can be used as a dust application ten days before harvest.
[7]

The Peach Tree Borer
This insect is a very serious pest, causing great damage to the base and roots of peach trees. It is the larval stage, commonly called borer, that does the damage (See Plate III). The moths emerge mostly in August and September and the females lay eggs on the trees and on trash and weeds up to about the first of October (See Plate IV). The borers hatch from the eggs, work their way into the base and roots of the tree and are all feeding by October 15th. They become full fed in the summer months and leave the tree to construct silken cocoons in the ground at the base of the tree. Here they pupate and the adult moths emerge in late summer and early fall. There is but one generation per year.
Control
Trees from one to three years old should be wormed by hand. Trees of these ages should be mounded up with four or five inches of dirt by the first of August. In November or December, these mounds should be taken down and the dirt removed from around the trees four or five inches below the natural soil level, thus making it easier to get the borers out of their tunnels. The best tools are a sharp hawk-bill knife and a stiff piece of wire to prod into and kill the borers deeply imbedded in their burrows. After worming is completed, the soil should be returned to the tree up to its natural level to prevent freezing in winter.
Trees four years old and older should be treated with pa.radichlorobenzene (See Plates V & VI). Only pure paradichlorobenzene should be used as the unsublimed and adulterated forms are apt to cause injury and to be ineffective. When properly applied, the sublimed paradichlorobenzene will kill 95 % or more of the borers, with no injury to trees four years old and older. It should be applied in north Georgia from September 25 to October 5; and in central and south Georgia from October 10 to 20.
Four and five-year-old trees should receive a three-quarter-ounce dose per tree. Trees six years old and older should receive a one-ounce dose per tree.
Before applying the paradichlorobenzene the soil for about a foot around the trunk should be cleaned of trash and grass and then smoothed with the back of a shovel. No mounding is necessary before applying except when the borers are working above the soil level; then the soil level should be raised so that the crystals are above the topmost borer galleries. The paradichlorobenzene should be applied in a circle around the trunk, about one inch from
[8]

the bark. About six shovelfuls of dirt are then placed in

a cone shape around the tree over the band and packed

down compactly. The first shovelful of dirt should be

shaken over the band carefully to avoid getting the crystals

against the trunk.



The mounds should be removed after four weeks from the four and five-year-old trees, and after six weeks from the six-year and older trees. Fresh soil should be returned to the tree to its original level before cold weather to avoid winter injury.

In case the fall application was not made, fairly effective results can be obtained by applying the paradichlorobenzene in the spring about April 1, in the same manner as given for the fall application. As high as 75 % of the larvae have been killed by the use of the spring application, but it is never as effective as the fall application because the larvae
are larger and harder to kill.

The Oriental Fruit Moth
The Oriental fruit moth is a comparatively new insect in the state, being first recorded in 1923 from Valdosta. Since that time it has spread all over the state where fruit is grown and is becoming a very serious pest, especially in the northern and upper middle sections of the state. There are from five to seven broods annually. The over-wintering larvae pupate in the late winter and the moths have been found laying eggs in March and the larvae begin entering the tender twigs during the month of April (See Plate VII). During the spring and early summer, the larvae attack only the twigs but as the later varieties of peaches begin to mature, m~ny larvae attack the fruit. They feed on the twigs until they become too hard for the newly hatched larvae to effect an entrance. It is the larval stage that causes all the injury and their work in the peaches is somewhat similar to the injury caused by the plum curculio (See Plate VIII). The average life cycle for each brood is about 35 days, although during the summer it is completed in a somewhat shorter time.
Control
Over-wintering cocoons on the ground can be killed if buried four inches deep in the soil. Careful plowing and deep cultivation in the spring about two weeks before blossoming time will bury the cocoons so deeply that the adults will not be able to reach the surface. Nearly as effective results may be obtained by similar cultivation in the fall, if growers prefer to do their orchard cultivating at that time.
[9]

All dropped fruit, especially those on the ground at, and after harvest, should be picked up and buried at least a foot below the soil surface so as to reduce the over-wintering population.
The usual fall application of paradichlorobem:ene for the peach borer will kill the cocoons on the trunk under the mounds and around the base of the tree.
Tests with hydrated lime sprays resulted in a 20 % to 35% reduction in the fruit moth as compared to the standard spray schedule. These results were obtained by adding 16 pounds additional hydrated lime to each 50 gallons of spray in the regular spray schedule and by using one extra application of hydrated lime and water at the rate of 20 pounds of lime to 50 gallons of water, half way between the third and fourth regular spray applications. Where selfboiled lime sulfur was used as the regular spray, approximately the same results were obtained as by the use of the extra hydrated lime with the proprietary sulfurs.
The best method of control is probably by means of natural parasites. One of the best of these is the egg parasite, Trichogramma minutum Riley, and these are now being bred artifically at the Parasite Laboratory of the Georgia State Board of Entomology at Cornelia and will be colonized and disseminated throughout the state as rapidly as possible, as a natural means of control of the fruit moth.
The San Jose Scale
The San Jose scale is a tiny, flat scale-like object, circular in shape with a raised tubercle in the center (See Plate IX). The female scale is about the size of a pinhead ; the male scale is slightly smaller and more elongated. The actual insect is underneath the scale covering and feeds there by inserting its tube or beak into the sap and pumping out the plant juices into its body.
Unlike many other insects, no eggs are deposited as the female ejects living young called crawlers. These young have legs and can move around. They soon settle down and feed, losing their legs and all means of locomotion, and at the same time forming a scale covering over themselves. There is a period of about thirty days in Georgia for each generation, so that there are many generations in one year and when they are breeding, all stages from crawlers to full-grown males and females can be found at the same time. The full-grown females are very helpless and have no wings or legs at any stage after the first day or two. The males, however, have legs and a single pair of wings when full grown and can fly in a feeble manner.
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Most of the injury is caused by the terrible speed that these insects multiply, the progeny from one female being estimated at 1,608,040,200 females in one season. In Georgia the greatest amount of breecling is done in the fall and spring. There is very little breeding in the summer or during the coldest parts of the winter. They hibernate in all stages but the ones that survive are mostly full grown females and half grown scales. It attacks all parts of the tree, including the fruit. Its greatest damage is done to the trunk and branches and will soon ruin a peach orchard if left unchecked.
Control
San Jose scale can be controlled by an application of either oil emulsion or liquid concentrated lime sulfur during the winter months while the trees are dormant. Use lime sulfur at the rate of one gallon to eight gallons of water or oil emulsion at the rate of nine gallons to 191 gallons of water.
Growers in the middle and southern districts from Thomaston south usually have very little trouble with leaf curl and can use either the lime sulfur or the oil emulsion for the control of scale. Growers in the northern district, however, frequently have severe infections of leaf curl and if using the oil emulsion for scale control, must use a 16-16-200 Bordeaux mixture with the nine gallons of oil emulsion.
All applications for scale should be put on when the trees are dormant and after all leaves have fallen. It is usually best to wait until there have been one or two killing frosts. The period from December 1st to February 15th is the best time for scale control in Georgia, and it is best to get the applications on early if there is a heavy infestation. Where trees are incrusted with scale, two sprays can be applied, one in December and one in February.
Dormant sprays must be applied carefully to give effective results. Scale cannot be controlled unless every part of the tree above the ground is covered with the spray material. Wherever possible, power outfits should be used having 250 pounds pressure in order to give a more uniform coverage without wasting material. It is advisable, if possible, to get the pruning done and prunings carried out of the orchard before the dormant sprays are applied.
Either the commercially manufactured or homemade lime sulfur or oil emulsion can be used. Commercial lime sulfur should have a density of from 31 to 33 degrees Baume at 60 degrees F. Commercial oil emulsion should contain not less than 66%. oil by volume exclusive of fatty acids.
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The following formulas for making lime sulfur, oil emulsion and Bordeaux mixture are given for those growers who desire to make their own scale and leaf curl control sprays on the farm.
How to Make Lime Sulphur Concentrate
The necessary ingredients and equipment for making are commercial ground sulfur, stone lime containing not more than 5% magnesium oxide, water, and a cooking vessel that will hold 75 gallons.
Heat about 10 gallons of water in the vessel and to it add 50 pounds of stone lime. When the lime begins to slack, add 100 pounds of sulfur by degrees, stirring all the while to break up the sulfur. After the sulfur is added and the lime slacked, dilute to 50 gallons and boil one hour. Water should be added at intervals to replace that which evaporates. Always keep the full 50 gallons in the vessel while the cooking is in progress. If not to be used at once, strain into tight barrels and cork. The density can be determined by an hydrometer according to the following table:

Table Showing Dilution of Lime Sulfur of Different Densities

Hydrometer Reading
Degrees on Baume Spindle

No. Gallons Water to Each
Gallon Solution

35

9

34

8%

33

81h

32

8

31

71h

30

7 14

29

6%

28

61h

Hydrometer Reading Degrees Baume
27 26 25 24 23 22 21 20

No. Gallons Water to Each
Gallon $olution
6 5% 514 5 41h 414 3% 31h

How to Make Oil Emulsion on the Farm
Cold Pump Formula : Red engine oil or oil of similar grade ______ 30 gallons Water ------- --- ------- ----------- - ---15 gallons Calcium caseinate --- ------- ---- ------ -- 4 pounds
Equipment necessary is two fifty-gallon barrels, one duplex or triplex pump and one three or four h. p. engine (the ordinary power sprayer with suCtion attachment). The four pounds of calcium caseinate is thoroughly beaten into two gallons of water in a bucket. This is then placed
[12]

in a 50-gallon barrel and 13 additional gallons of water added and thoroughly stirred. Then add the 30 gallons of oil and stir again. Then place suction hose .into barrel and start motor. Allow ingredients to be sucked through the pump under 250 pounds pressure and out through the spray rods with discs removed or with discs with 3/ 16 inch hole into another 50-gallon barrel. Repeat the operation until all the ingredients have passed through the pumps three times. This type of oil emulsion should be made daily as required.
How to Mak~ Bordea.'UX Mixture and Mix With Oil Emulsion
Suspend 48 pounds of bluestone in a sack at the top of 48 gallons of water in a clean wooden barrel ; this will dissolve in 24 hours or less, if air is allowed to come in contact with part of the bluestone. Slack 48 pounds of stone lime into a thick paste and then make it up to 48 gallons by adding wate~. Measure out 16 gallons of the copper sulphate solution (bluestone) after thorough stirring, and pour into a spray tank that has been filled about two-thirds full of water. After thorough stirring, pour slowly through a strainer 16 gallons of the stock lime solution into the spray tank with the motor and agitator running. The nine gallons of oil emulsion should be added while the motor is running and then fill the tank to the 200-gallon capacity. Proportional quantities should be used for tanks of other than 200-gallon size. The amount of material as listed will make three tanks of Bordeaux Mixture of the 4-4-50 strength.
Important Peach Diseases
The four most important peach diseases are brown rot (Scle1otinia cinerea), peach scab (Cladosporium carpophilum), leaf curl (Exoascus deformans) and bacterial spot (Bacterium pruni). The first three are fungus diseases and the last named, which is commonly called bacteriosis, is a bacterial disease. All of these diseases call for special control measures by peach growers to avoid serious losses.
Brown Rot
This disease attacks fruit, twigs and blossoms but is of most serious consequence on ripening fruit. In the spring about blossoming time under favorable weather conditions, the disease enters the blossoms and twigs, frequently killing them outright. It first appears on the fruit as a small circular brown area which rapidly enlarges until the entire fruit becomes a soft brown rot, giving off thousands of spores which infect other peaches (See Plate X). If left on the trees these rotten peaches mummify and turn black
[13]

and either hang on the tree or drop to the ground and furnish spores for reinfection the following year. The disease is very bad during the warm humid weather, especially when there is a heavy curculio infestation. The curculio punctures the peach skin for feeding purposes or egg laying and these skin ruptures make an easy place for the brown rot spores to enter so that the control of the curculio is one of the first essentials for the satisfactory control of brown rot.
Control --
The best fungicidal control for brown rot is self-boiled lime sulfur. Other tested proprietary sulfurs put out by different manufacturers are very good substitutes for the self-boiled lime sulfur and should be used according to the directions given on the package and applied at the time indicated for the application of self-boiled lime sulfur. Spraying directions are given on page 6 in the combined schedule for the control of the curculio, brown rot and scab, together with directions for making self-boiled lime sulfur on the farm.
The removal of mummified fruit and rotten peaches from the trees and ground is necessary for good control. These mummies and rotten fruits should be taken from the orchard in summer and fall and buried several feet in the ground to prevent the fruit from giving off spores and starting infection the following spring.
. Peach Scab
This is a disease of the fruit, twigs and leaves but is most serious on the fruit. It first appears as small olive to brown spots on the surface, gradually enlarging and sometimes fusing and turning darker until they become nearly black. It causes the skin of the fruit to become tough so that it will not expand with the normal growth resulting in cracked and miss_hapen fruit (See Plate XI).
Control
The combined. spray schedule for peach insects and diseases given on page 6 will control scab in Georgia.
Leaf Curl
In unsprayed or improperly sprayed orchards, leaf curl is a serious disease in the northern half of the state, but is of little consequence in the middle and south Georgia peach belt. It works almost entirely on the new growth causing
the unfolding leaves to become swollen and distorted and
[14]

InJuring the blossoms and twigs (See Plate XII). Af-

fected leaves become puffed and twisted with much thick-

ening along the midrib and veins, acquire a reddish color

and later become brown and drop off. The worst injury

from leaf curl occurs when the spring is cold and the rains

are frequent. During dry, sunshiny weather, the disease

is of minor consequence.



Control
This disease can be controlled by an application of either concentrated lime sulfur solution or Bordeaux mixture. If spraying for scale, the lime sulfur used at the rate of one gallon to eight gallons of water, will control leaf curl. If using oil emulsion for scale, add a 4-4-50 Bordeaux mixture to control the leaf curl. If spraying operations are directed against leaf curl only, the Bordeaux mixture alQne or liquid concentrated lime sulfur one gallon to water 15 gallons, will control the leaf curl. The important points to remember in spraying for leaf curl are thoroughness and timeliness. The whole of the tree above ground and especially the buds, must be CQvered with the spray and it must be applied while the trees are dormant and before the buds have started to swell.

Bacterial Spot
While this disease has been known for more than twenty years in the state it is only in the last few years that it has become of much economic importance. It is much worse on the light gray lands, on weak and undernourished trees, and it also shows a decided preference for the Elberta variety. It is a bacterial disease and commonly called bacteriosis. It attacks the leaves, twigs and fruit and frequently causes premature defoliation. The first indication of its presence is small irregular dark spots on the leaves which later cause shot-holing and finally the leaves turn yellow and drop off (See Plate XIII). On the fruit it appears first as a small purple spot where the skin cracks and finally results in a cracked brownish area that may extend over most of the surface (See Plate XIV).
Control
To prevent this disease from becoming serious it is especially important that the trees be planted on a good grade of land and kept in a high state of cultivation. Any treatments that improve the vigor of the tree such as cover crops and fertilization, will check the disease. Three pounds of nitrate of soda per bearing tree, applied early in May fullowed by cultivation, will reduce the amount of injury.
[15]

Zinc sulfate and hydrated lime applied as a spray, beginning when the petals fall, has proven to be a good control. It is used at the rate of four pounds of zinc sulfate and four pounds of high-grade hydrated lime to 50 gallons of water. Five to seven applications at two-week intervals throughout the season, are generally required. It can be mixed with arsenate of lead in the regular spray schedule. In applying, it is necessary to cover the under side of the leaves and all new bud growth, as well as the fruit. In preparing the spray, fill the tank nearly full of water and start motor. Then add the zinc sulfate which will dissolve in about five minutes. The lime is then mixed with water to form a thin paste and this is then strained into the tank. Finish filling tank, agitate for five minutes and then start spraying. Good agitation is necessary as without it the mixture settles rapidly.
Phony Peach
This is another of the virus diseases but is different from rosette and peach yellows in that it does not kill the tree. In fact, the phony trees in the orchard appear to be vigorous and healthy but yet do not look like a normal tree. The leaves are greener and larger, the twig growth is much shorter and the tree itself is smaller than the normal peach tree. Trees affected with this disease do not show the first symptoms until after the second year. While the causitive agent is not known, it has been definitely proven to be infectious through the roots. This disease has been found only in Georgia, Alabama, and one locality in Mississippi, and is particularly bad in middle Georgia. In the Fort Valley peach section many orchards show over 50 % phony trees. As the disease progresses, the bud wood gets shorter, the fruit smaller and the yield is soon so reduced that the tree becomes of no value.
It cannot be controlled with any sprays, dusts or cultural practices. The best thing to do is to cut out and destroy affected trees. The U. S. Bureau of Plant Industry and the Georgia State Board of Entomology are now conducting a joint campaign for the eradication of this disease. The whole peach area in the state is being inspected, the phony , trees marked and all such trees removed as rapidly as possible. This is believed to be the only practical control method and it is estimated that most of the phony trees will be eliminated from the state within five years. Growers should cooperate with the government and state officials in this work and aid in every way possible, because in the past few years this disease has spread very rapidly and if not checked will probably wipe out the Georgia peach industry.
[16]

Less Important Peach Insects and Diseases
Other insects attacking the peach in Georgia are the shothole borer (Scolytu"S rugulosus), lesser peach borer ( Aegeria pictipes), peach twig borer ( Anarsia lineatella), the corn ear worm (Heliothis obsoleta) and several species of grasshoppers. Other diseases are Crown gall (Bacterium tumefaciens), rosette, peach yellows and phony disease. A nematode worm (Heterodera radicicola) also causes some injury to the root system.
The shot-hole borer attacks the branches and trunk, usually choosing trees weakened by other insects, diseases and winter injury. It causes the tree to send out great quantities of gum through exit holes made by the beetles. The tree when severely infested, is covered with tiny holes about the size of bird shot. The best control is to cut out and burn badly infested trees. Trees lightly to moderately infested should receive a coat of whitewash in June and again in August. To each ten gallons of whitewash, add one pint of crude carbolic acid as a repellent.
The lesser peach borer injures the tree in a similar manner to the peach borer except that most of the damage is done above ground, especially in wounds caused from farm implements. If the trees are kept free from mechanical injury, this insect does very little damage. When the tree becomes infested, it should be wormed by hand as directed for the peach borer.
The peach twig borer is a small dark reddish brown worm that bores into the twigs and occasionally into the fruit. It is of little economic importance in Georgia and can be controlled just as the blossoms are beginning to open with lime sulfur concentrate one gallon, to water ten gallons; or lead arsenate l ljz pounds to water 50 gallons.
The corn ear worm occasionally injures peaches, especially when vetch has been planted in or near the peach orchard. When feeding on vetch, the worms become very numerous and feed and migrate similar to army worms. When the worms are nearly full grown, they leave the vetch and finish off feeding in the green peaches. They can be controlled by making a deep furrow between the vetch field and the peach orchard with the side next to the peach orchard made very steep. Post holes should be dug at frequent intervals in the furrow to trap the worms and these can be killed by crushing. If the vetch is planted in the orchard, poison bran bait should be broadcast or the orchard sprayed or dusted with arsenate of lead, as recommended for the curculio. A formula for making poison bait is given on page 22. It is better never to plant vetch in or near a peach orchard.
[17]

Several species of grasshoppers feed on peach fruits and foliage, especially in the spring when the peaches are small. They can be controlled with the poison bait formula given on page 22, by spraying with arsenate of lead (the shuck spray in the standard spray schedule) and by plowing the orchard before the eggs, which are laid in the ground, can hatch. Hatching occurs in Georgia during March and April.
Crown gall is a common disease in the orchard but particularly bad in the nursery and on young trees. The disease is known in two forms: a hard callous on roots and crown; and a kind called hairy root which forms thick masses of fine roots that choke out the lateral healthy feeding roots. If diseased nursery stock with either kind of gall is planted, it develops in the orchard and frequently kills the trees after a few years' sickly existence. No cure is known after it gets into the tree. The best preventive is to plant clean nursery stock, properly inspected by state inspectors.
Rosette and peach yellows are occasionally found in the state. They are infectious virus diseases from which the causitive organisms have never been isolated. The rosette disease gets its name from the stunted growth and abnormal number of shoots which gives the tree a peculiar rosetted appearance. The foliage falls prematurely and the tree dies within two years after the first symptoms appear.
Yellows cause the fruit to ripen prematurely and the fruit has red spots on the surface and streaks in the flesh. The foliage turns yellow and the shoots form numerous clusters. The tree affected dies within three years after the first symptoms are noted. The control for both rosette and yellows is to dig up and burn the affected trees.
Nematode Worm
The microscopic nematode worm (Heterodera radicicola) is commonly found feeding on the roots of peach trees and under certain conditions, becomes very injurious. It makes knots or galls on the feed roots, stunts the growth and in severe attacks, kills the trees, especia,lly young trees. This worm also feeds on other plants growing in the orchard such as cotton, watermelon, cantaloupe, soy bean, potato, tomato, cow peas and some weeds. The best control is to avoid planting orchards on land known to be infested with this worm. The light sandy lands are particularly apt to be infested. If peas are used as an orchard crop, only those immune varieties such as Brabham, Iron or Iron hybrids, should be planted. Soils infested with nematodes can not be freed of them except by rotation of crops immune to attack. If trees are kept in a high state
[18]

of vigor and planted on a good grade of land, this worm is not apt to give serious trouble.
Beneficial Insects and Diseases
The beneficial insects are called parasites and predators. Certain fungi are also beneficial in that they feed on and kill many insects. These three factors account for the reduction of many of our important orchard pests and are a great natural aid to the growers, often doing more to check the insect pests than such artificial control measures as spraying and dusting.
The San Jose scale is frequently found in the orchard with a tiny hole in the center of the scale covering which is the exit hole of any of several species of tiny hymenopterous parasites. One of the most important and widely distributed of these is Aphelinus fuscipennis. Others parasitizing the San Jose scale are Aphelinus mytalaspidis, Aspidiotiphagus citrinus, and Prospalta aurantii. A very important predator is Chilocorus bivulnerus which feeds on the scale insects throughout the year. This predator is commonly called the twice stabbed lady bird oeetle and is a small round black beetle with two red spots, one on each wing cover. Most growers have seen this little beetle in their peach orchard running about looking for scale insects on which to feed. The San Jose scale is also attacked by the red head fungus (Sphaerostilbe coccophila) and the black fungus (Myriangum duriaei).
The plum curculio has two important parasites that sometimes kill a high percentage of eggs and larvae. They are both wasps, one being the egg parasite ( Anaphoidia conotracheli) and the other the larval parasite (Triasphis curculionis). Both of these parasites are common and abundant in Georgia.
Very few parasites have been recorded on the peach tree borer and those recorded parasitize a very small percentage of the host. An egg parasite, Telenomous quaintancei, is probably the best of the lot. The praying mantis which is quite common in Georgia has been noted lying in wait at the base of peach trees and pouncing upon the adult moths as they emerge from the cocoons and also while the female moth is depositing eggs.
The Oriental fruit moth is attacked in the egg stage by the egg parasite Trichogramma minutum and in the larval stage by Macrocentrus ancylivora. A white mold has also been found killing the larvae in cocoons, mostly around the base of the tree or on the ground. The two parasites mentioned are rarely found naturally in Georgia. It has been found that the egg parasite, T. minutum, can be bred in large numbers in a laboratory and such a laboratory has
[19]

been established by the Georgia State Board of Entomology. This laboratory was started in 1929 and over two million of these parasites were bred and distributed throughout the state. It is planned to breed many millions of these parasites each year and send them out to peach growers so that they can establish themselves in the peach orchards and parasitize the eggs of the Oriental fruit moth, thus acting as a check on this very serious peach pest.
Other parasites and predators of some value in the peach orchards are Syrphid fly larvae, lace wing fly larvae, Tachinid flies, assassin bugs, ground beetles and several species of lady bird beetles.
Insecticides and Fungicides
The following chemicals are used as insecticides and fungicides for the protection of the fruit and tree by peach growers in Georgia : arsenate of lead, stone and hydrated lime, sulfur, copper sulfate, self-boiled lime sulfur, liquid concentrated lime sulfur, zinc sulfate, lubricating oil emulsions, paradichlorobenzene, dust mixtures, several proprietary sulfur compounds, miscible oils and poison bran mash.
Arsenate of Lead: This is the only form of stomach poison that has proven to be satisfactory and safe to use on peach trees. The powdered form is practically the only one in commercial use and it should contain not less than 30% total arsenic pentoxide, not more than 0.5 % water soluble arsenic pentoxide and not more than 0.3 % total arsenic trioxide. It is a finely divided powder and will stay in suspension with ordinary agitation as provided in power or hand spray outfits. Reasonable precautions against burning the fruit and foliage should be taken when using this material. It should not be used stronger than one pound of lead arsenate to 50 gallons of water and should not be applied when the trees are wet or when the temperature is above 90 degrees F. For each pound of lead arsenate used, there should be added either 3 pounds of stone lime or 4 pounds of hydrated lime to each 50 gallons of spray material.
Stone and Hydrated Lime. Stone and hydrated lime is used as a neutralizer for lead arsenate and in combination with sulfur and bluestone to make such materials as selfboiled lime sulfur, liquid concentrated lime sulfur and Bordeaux mixture. Hydrated lime is also used as a filler in various dust mixtures. Only a good grade of lime should be used for spraying and dusting and should contain not less than 90 1'o calcium hydroxide.
Sulfur. Sulfur, combined with other chemicals, is one of the most important materials used for spraying and dusting peach orchards, as some of the combinations act both as
[20]

insecticides and fungicides. Various forms are in use, such as ground brimstone, flowers of sulfur and super-fine sulfur. It is practically always clean and pure as received from the manufacturers.
Copper SUlfate. Copper sulfate (bluestone) is combined with either stone or hydrated lime to make Bordeaux mixture. Bordeaux mixture is unsafe to use when the peach trees are in foliage but can be used as a dormant application in the winter as a control for leaf curl. There are several formulas of this mixture such as 2-2-50, 3-3-50 and 4-4-50. The 4-4-50 is the one most commonly used and directions for ma).dng this strength are as follows :
Copper sulfate (bluestone) _____ ____ ___ __ 4 pounds *Stone or hydrated lime_____ ______ ___ ___ _ 4 pounds
A better product results if stone lime is used. Water ________ ____ ____ ____ __ _______ ____50 gallons
Dissolve the bluestone in a 50-gallon wooden barrel containing 25 gallons of water, by suspending it in a sack just beneath the surface. Slack the lime a little at a time in a second barrel and dilute to 25 gallons. Pour the two mixtures together simultaneously, a bucketful at a time, through a strainer into a third barrel or directly into the spray tank. Directions for making and mixing Bordeaux mixture and oil emulsion will be found on page 13.
Self-Boiled Lime SUlfur. This is the oldest and probably the best remedy for the control of brown rot. It will also control scab. Directions for making and how to use will be found on page 7.
Liquid Concentrated Lime SUlfu1 Solution. This is an old remedy for the control of the San Jose scale and is also used as a control for other scale insects and leaf curl. Directions for using and making on the farm will be found on page 12. The commercially manufactured product is in very wide use by the growers and this should test from 31 degrees to 33 degrees Baume at 60 degrees F. and contain not less than 29 7o of calcium polysulfides.
Zinc SUlfate. This product has recently come into use as a control for bacterial spot. It is combined with hydrated lime at the rate of 4 pounds of zinc sulfate and 4 pounds of hydrated lime to 50 gallons of water. With the power outfit running and with the spray tank about twothirds full of water, add the required amount of zinc sulfate and then the hydrated lime. Sixteen pounds of each should be used for the ordinary 200 gallon outfit. It can be mixed with arsenate of lead.
Lubricating Oil Emulsion . The oil emulsions are both commercially manufactured and home made. The commercial oil emulsion should contain not less than 66 7o oil by
[21]

volume, exclusive of fatty acids, and have a viscosity by the Saybolt test of not less than 125 seconds at 100 degrees F. Oil emulsions in Georgia are used almost entirely as a dormant control of the San Jose scale and at the 3% strength, which is 9 gallons of oil emulsion to 191 gallons of water. Directions for making homemade oil emulsion will be found on page 12.

Paradichlorobenzene. This chemical is used to control the peach tree borer and as a partial control for the Oriental fruit moth. It should be not less than 98 7o pure sublimed paradichlorobenzene and of the fineness of granulated sugar
or fine flakes. It should never be used on trees in Georgia that are less than 4 years old. Complete directions for its
use will be found on pages 8 and 9.

Dust Mixtures. Peach dust mixtures contain powdered lead arsenate, hydrated lime and finely ground sulfur. Not
less than 95 % of the sulfur and 90 % of the mixture should be fine enough to pass through a 200 mesh screen. The 80-5-15 mixture containing 80% sulfur, 5% lead arsenate and 15 % hydrated lime is the one most widely used as a dust control for curculio, brown rot and scab. Other dust mixtures used are the 0-5-95, containing 5% lead arsenate and 95 % hydrated lime; 90-10, containing 90 % hydrated
lime and 10 7o lead arsenate. The 0-5-95 is used as the first dust in the regular peach dust schedule and the 90-10 as an
after-harvest control of the curculio.

P1op'rieta1y Sulfur Compounds and Miscible Oils. Several

proprietary sulfur compounds and miscible oils are on the

market and are used as a control for various peach insects

and diseases. If they have been thoroughly tested by ex-

periment stations and growers, it is safe to use them as

.

recommended by the manufacturers. All such products

should be labeled so that the grower can know the total

percentage of active and inactive ingredients. The sulfur

compounds are used mainly as a control for the plant dis-

eases such as brown rot and scab, while the miscible oils

are mainly used as scalecides during the dormant period.

Poison Bran Mash-
Bran ----------~ --- --------------------25 pounds White arsenic -------------------------- 1 pound Black strap molasses -------------------- 2 quarts Amyl acitate (good grade)---------- -- ---% ounce
Mix the bran and white arsenic drv and then add the black strap molasses and amyl acitate diluted with enough water to make a slightly moist mash. Broadcast at the rate of 10 pounds per acre. This mash is used as a control for grasshoppers and the corn ear worm in peach orchards.

[22]

PLATE I
aches i n the right stage for the second application in the standard spray schedule
wh i ch is the most important for the control of the curculio
[23 ]

PLATE II Curculio Larvae (grubs} feeding in ripe fruit
[24]

PLATE Ill The peach tree borer and its work
in the trunk and main roots
PLATE IV Adult female peach tree
borer
[25]

PLATE V
One ounce of paradichlorobenzene spread in even band one inch from base, ready for
covering
PLATE VI The mound of soil over the ring of
dichlorobenzene
[26]

PLATE VII Newly infected peach twig showing one wi Ited leaf and pile of frass where Oriental fruit moth lava has entered. (U. S. D. A. Bureau of
Entomology)
PLATE VIII An infested peach split open to show Oriental peach moth lava and injury.
( U. S. D. A. Bureau of Entomology )
[27]

PLATE X Peach infected with Brown
Rot, showing spore masses
PLATE IX San Jose Scale on Peach Limb
[28]

PLATE XI Scab on Ripe Peaches
[ 29 ]

PLATE XII Peach Leaf Curl
[30]

PLATE XIII Bacterial spot on peach foliage (U. S. D. A. Bureau of
Plant Industry)
PLATE XIV Bacterial spot of peach ( U. S. D. A. Bureau of Plant In-
dustry)
[31]

GEORGIA STATE BOARD of ENTOMOLOGY
M. S. YEOMANS, State Entomologist

BULLETIN No. 72

March, 1930

Experimental Dusting an.tl Spraying of Watermelon
Anthracnose
0 . C. BOYD, Plant Pathologist

STATE CAPITO GENERAL Ll BRAR LANTA,GA.
MAY 11 1:1':to UNIVERSITY OF GEORGIA

GEORGIA STATE BOARD OF ENTOMOLOGY
Organization and Staff HON. EUGENE TALMADGE, Commissioner of Agriculture, Atlanta.
HON. A. MITCHELL METCALF, Clarkesville.
HON. T. W. HOLLIS, Buena Vista.
M. S. YEOMANS, State Entomologist and Secretary of the Board, Atlanta
CHARLES H. ALDEN Entomologist, Cornelia.
J. B. GILL, Entomologist, Albany.
TOM O'NEILL Entomologist, Atlanta.
D. F. FARLINGER, Assistant, Cornelia.
D. C. MOODY, Assistant, Cornelia.
J. H. GIRARDEAU, Chief Inspector, McRae.
C. H. GADDIS, Inspector, Albany.
A. B. HAMLIN, Inspector, Macon. J. D. FULLER, Inspector, Mountville. JOHN F. MONROE, Inspector, Athens.
2

CONTENTS
Page (Introduction) ___ ___ __ ____ _____ __ __ __ _____ ____ ____ 5
Experiments in anthracnose controL ______ __ __ _______ 6 Plan and purpose of the project_ ______ __ ___ ___ __ ___ 6 Experiment of 1924 __ ____ ______ ___ _______ ____ ____ 7 Methods and materials _______ __ __ _______________ 7 Observations on anthracnose control in 1924__ __ ___ 8 Relation of dusting and spraying to yield, prevention of anthracnose, and net returns in 1924__ ____ ___ 8 Experiment of 1925 ______________ _________ _______ 9 Methods and materials __ _________ _____________ __ 9 Observations on anthracnose control in 1925 _______ 9 Yield, control of anthracnose, and net r eturns in 1925 ------ - -- - -- --- - --- --- ----------------- 10 Experiment of 1926___ _________ ___ _______________ 10 Methods and materials __ _____ __ __ _________ ___ __ _10 Observations on anthracnose control in 1926 ___ ____ 12 Yield, anthracnose control, and net returns in 1926__13
Discussion of methods, observations, and results for the three years' work _________ ___________ ____ ______ 13
Effectiveness of the dust and spray treatments in anthracnose control ------ --- ----------- - ------- - - 13
Dusting and spraying materials___ _________ __ __ __ __ 15 Rate of application of fungicides- - -~--- - -------- --- 17 Time, number, and frequency of applications ________ _17 Machinery for dusting and spraying _______ _______ __18
Sprayer ----- - ----------- ------------------ ---18 Duster ---- - ------------- - --- -- -- - -------- - -- -19 Demonstration of dusters and dusting attachments __ 20 Time required for dusting and spraying watermelons __ 22
(Continued on next page)
3

CONTENTS- (Cont inued)
Page Efdfuecsttionfgw_i_n_d__a_n_d_l_e_a_f_m__o_i_st_u_r_e_o_n__s_p_r_a_y_in_g__a_n_d_____ _22
Injurious effects from dusting and spraying __ ________ 23 Cost of dusting and spraying watermelons ___ ___ _____ 24 Praonfitthirnacdnuosstein_g_ _a_n_d__s_p_ra_y__in_g__w_a_t_e_rm__e_l_o_n_s_a__ga_i_n_s_t___ 26
Application of methods and results to growers' conditions --- ------ - -- - ------ - -------- -- - - -- --- -- -- 27
Relation of methods in growing and marketing melons to anthracnose losses and crop protection____ ______27
Factors affecting the advisability of protecting melons against anthracnose __ ____ ____ _______ ____ _____ __ 28
Application of a specific example ________ _____ __ ____ 29
Recommendations for anthracnose controL ________ ____ 31 Practices other than protection ___ __ __ ____ __ __ __ ___ _31 Field selection and rotation ____ __ __ __ ___ ____ _____ 31 Time of planting ___ ______ ________ ____ _____ __ ___ 31 Seed selection_______ ___ __ ___ _____ ___ __ ___ _____ _31 Seed disinfection _____ ____ ___ ______ __ __ _____ ____ 31 Field sanitation __ ___ ____ ___ _____ _____ ___ __ __ __ _32 Field protection with dust or spray_____ ____ ___ ___ __ 32 Method to use, dusting or spraying __ _________ __ __ 33 Machinery to use___ ____ __ __ ___ ___ ____ ___ __ __ ___33 Materials to use___ ___ ___ ___ ___ ___ ____ ___ ___ ____33 Preparation of Bordeaux mixture ___ __ ________ ___33 Copper-lime dust and its preparation ______ __ ____ 31 When to spray or dusL ________ __ ____ ______ _____ 35 How to spray or dust_ _____________ __ __ ____ __ ___35 Precautions in dusting and spraying watermelons ____ 35
Summary ______ ____ ___ ____ _______ ______________ __ 36
4

EXPERIMENTAL DUSTING AND SPRAYING FOR
THE CONTROL OF WATERMELON
ANTHRACNOSE
0. C. BOYD, Plant Pathologist
The watermelon crop of Georgia has long been considered one of the state's outstanding agricultural resources. This state, furthermore, leads all others in the production of this commodity for the early market. Parallel with the advancement of the industry has occur:red an increasing interest in methods of production and marketing. Only within the past few years, Georgia has experienced the inception and remarkable progress of one of the country's most successful cooperative growing and marketing organizations of farm products, namely, the SOWEGA Melon Growers' Association with headquarters at Adel, Ga. This organization is continually reporting interesting facts learned in regard to the intimate relations that exist among the following subjects: The organized growing, packing, and selling of melons and other farm products; the importance of quality production; advertisement of the product, and the consideration of supply and demand in marketing; together with the ultimate returns and profit the grower receives for his crop.
Hundreds of farmers of the state include regularly the melon among their standard crops. The estimated total carlot shipment of commercial melons for the years 19201928 are as follows: 9,980, 15,041, 13,418, 7,222, 16,347, 14,751, 19,354, 16,762 and 16,595, respectively. This does not include the extensive small plantings for home consumption and local distribution.
The watermelon, like practically all other crop plants, has its numerous maladies. Due to its perishable character in transit and on the market, furthermore, it is subject to a number of post-harvest diseases and other handicaps in addition to the usual field troubles and weather hazards experienced during the growing season. Of all the diseases with which the melon grower must contend, anthracnose is, perhaps, generally the most common, best known, and most destructive. It causes not only a spotting of the leaves and runners, resulting in premature defoliation with undersized and sunburned melons, but a spotting and decay of the fruit as well (figures 1, 2, 3, pages 39, 40, 41). It is the fruit decay stage of the disease, known as "pox," that frequently is responsible for heavy losses in transit and on the market. Although this form of the disease develops largely after
5

harvest, yet it has its origin in the field where the casual organism is spread from infected vines to the melons.
A review of the loss estimates for anthracnose alone in this state, based upon reports of the U. S. Department of Agriculture Plant Disease Survey office, reveals the following figures for the past few years: 1921, 30-40 per cent; 1922, 25-30 per cent; 1923, 50-60 per cent; 1924, 25-30 per cent; 1925, 10 per cent; 1926, 20 per cent; 1927, 15 per cent; 1928, 25-30 per cent. These estimates include only the losses in the field and at loading stations, and do not take into account the losses that developed later in transit. A citation of estimates of anthracnose losses made during terminal inspection of carlots from Georgia by the U. S. Department of Agriculture Inspectors will serve to indicate the extent of damage from this disease during transit (figure 5, page 42). These estimates cover two years of severe blighting of vines and poxing of melons in the field, and one year of light infection. In 1921, of the 183 cars that showed anthracnose decay, 18 cars showed 75-100 per cent of the melons rotting; 27 with 50-74 per cent decay; 40 with 25-49 per cent decay; 8~ with 5-24 per cent decay; 9 with 1-4 per cent decay, with an awrage of 30 per cem decay for the 183 cars. In 1923, another heavy anthracnose season, of the 128 cars inspected, 47 showed 25 per cent or over of anthracnose decay; 66, 10 per cent or over; and 76, 5 per cent or over, with an average of 23.8 per cent decay. In 1927, a season of unusually light damage from anthracnose, of the 212 cars inspected, 28 showed 25 per cent or over of decay ; 49 cars, 10 per cent or over; and 56 cars, 5 per cent or over, with an average of 9.1 per cent for the 212 cars. It is little wonder, following the years of 1921, 1922, and 1923, that the growers, generally, made repeated inquiries for means of controlling this melon disease.
EXPERIMENTS IN ANTHRACNOSE CONTROL
PLAN AND PURPOSE OF THE PROJECT
Following the three successive seasons of heavy losses from anthracnose, 1921-23, requests were received from all watermelon sections of the state for advice on means of preventing the reoccurrence of such losses. Although information was available at the time regarding the effectiveness and practicability of spraying watermelons against anthracnose, based upon four seasons of experimental work1 in southern melon fields, one season's work of which was conducted in the central part of Georgia, the growers of
11\leler , F. C. Control of wate rm elon anthracnose by SJ>r,.yln g. U . S. D. A. Dept. Clrc. 90, 1920. Note : The spra ying d e mons trations In G e orgia w e r e conducted a t Dry Branch and J effersonville In 1917.
6

this state were not following recommendations for spraying. Inasmuch as the dusting of field and orchard crops at that time was of considerable interest generally, it was planned to begin an experiment with the use of dusts along with Bordeaux mixture for the control of anthracnose. The purpose of the experiment was to test the effectiveness of both the dry liquid fungicides, and to ascertain the applicability of dusting to general farm conditions in comparison with spraying. Accordingly, in the spring of 1924, the project was initiated at the Thomasville field station located in the southwestern part of the state. Dusting was undertaken on a limited scale, with use of hand machines only. Should dry fungicides prove sufficiently effective against anthracnose it was the intention to extend the method to conditions applicable to the growers' needs. Since spraying had already been given a thorough trial under field conditions in the state, that method of treatment was considered not so far in the experimental stage as dusting.
EXPERIMENT OF 1924
METHODS AND MATERIALS
The experimental plot comprised 3.6 acres with rows spaced ten by twelve feet. The 12-foot rows were used for plats. The standard variety, Tom Watson, was planted. The fungicides under test included home-made Bordeaux mixture with and without the casein spreader, Kayso, homemade monohydrated copper sulphate-hydrated lime dust containing 25 per cent of the copper salt, and a similar dust of the same percentage of copper furnished by the Skinner Machinery Company, Dunedin, Fla. The series, including an untreated or check plat, was repeated three times across the field with a fourth plat of each of plain Bordeaux mixture and check. The dust and check plats contained two rows each, or 0.17 acre, and the sprayed ones three rows each, or 0.25 acre. The dusters in use were the fan type of hand machines, each with a six-foot pipe and spreading nozzle. The spray rig consisted of a Hardie "Magic" truck crop sprayer with a three-cylinder pump and four horse-power gasoline engine, mounted upon a 150-gallon tank. Two leads of hose sufficiently long to cover two rows on each side of the machine were equipped with five-foot bamboo rods, each with one nozzle while the vines were small, and with two nozzles later in the season for heavier vines. A pressure of 175-200 pounds per square inch was maintained throughout.
The dust applications were made in the early morning on wet vines, and the spray applications later in the day
7

on dry vines. The number and dates of applications, together with the time required and the amount of fungicides used, are indicated in table 1. The labor involved consisted 'of two men in dusting and three men with two mules in spraying.
OBSERVATION ON ANTHRACNOSE CONTROL IN 1924
Anthracnose was first observed on May 27 as a few spots on the older leaves of a single hill of the fourth check plat. On June 17, the date of the fourth applications, the disease appeared to be still limited to the one hill, but the spots were increasing in numbers. By June 25, leaf spots were observed throughout all of the check plats with a trace in the treated rows. On July 8, date of the sixth application and of the first harvest, each check plat contained several areas with all hills completely defoliated and showed a general, rapid spread of infection throughout them. The progress of infection in the treated rows was very slow in comparison, with slightly more anthracnose in the dusted than in the sprayed vines. At this time, poxed melons were numerous in the check plats, while only an occasional one was to be found in the protected plats.
On July 15, the date of the second harvest and one day before the last application, all of the foliage in the first check plat was dead, about 90 per cent in the second and fourth, and 75 per cent in the third one. There was ob~ served at this time a light, scattered infection throughout all of the treated rows with noticeably more in the dusted vines. On the melons, infection was developing rapidly in the untreated vines, the second harvest showing 73 per cent of the melons prominently poxed. In the protected plats, on the other hand, the percentage of poxed melons was from 3-12 per cent. On July 25, eight days after the last application, and the date of the last picking, the unprotected plats appeared as brown streaks among the dusted and sprayed rows, and contained only scattered patches of green foliage which were heavily spotted with anthracnose. In the last harvest, the number of poxed melons ranged from 23-32 per cent for the treated plats, as compared with 80 per cent for the check plats. During the last two harvests, the unprotected plats yielded 391 undersized, immature, sunburned melons per acre, due to premature defoliation from anthracnose, which amount equaled 64.2 per cent of their total yield. This type of loss did not occur in the dusted and sprayed plats.
RELATION OF DUSTING AND SPRAYING TO YIELD, PREVENTION OF ANTHRACNOSE, AND NET RETURNS IN 1924
Data on yields and anthracnose control occur in table 3; on cost of dusting and spraying, in table 2; and on the mar-
8

ket value and net returns of the melons harvested, in table 4, page 46. A discussion of these subjects for the three years' experiment occurs on page 13.
EXPERIMENT OF 1925
METHODS AND MATERIALS
The history of the experimental field for the second year, including materials and methods generally, was similar to that for the first year. It involved the same size field, same machinery, and same fungicides with the omission of the spray formula with the spreader. There were three replications of the plat series. The dusted plats comprised three rows each, or 0.25 acre, and the sprayed and unprotected ones four rows each, or 0.34 acre. The strength of the copper-lime dusts was reduced to 20 per cent of monohydrated copper sulphate, and the formula of Bordeaux mixture changed to 3-6-50 for the first two applications and 4-8-50 for the remainder. The dust applications, furthermore, were made on dry vines, usually in the late afternoon when the air was quiet. Information regarding the number and dates of applications and the amount of materials for each, is included in table 5, page 46; and for the cost of spraying and dusting, in table 6, page 46.
OBSERVATIONS ON ANTHRACNOSE CONTROL IN 1925
This season, as in 1924, anthracnose was the only disease of importance in the experiment. It was first observed on May 25, the date of the second application of fungicides, as a few leaf spots in a hill of one of the dusted plats. On June 6, the date of the third application, three lightly infected hills were found in one of the check plats, eight in another, and fourteen in the third one. The treated plats, excepting the one affected vine in the dusted plat, appeared free from the disease. A week later, anthracnose was present in all four rows of each unprotected plat, with an occasional poxed melon noticeable. On June 20, the date of the fifth application and four days prior to the first harvest, practically every hill in the unprotected rows showed leaf infection with the majority of the older melons poxed. Occasional hills throughout the treated rows, also, showed recent development of the disease on both leaves and melons. On July 1, the date of the second harvest and two days after the last dusting and spraying, there was evidence of recent, rapid spread of anthracnose on both leaves and fruit in all check plats. A few hills there were completely defoliated, and about 85 per cent of the melons prominently poxed. The disease at this time was spreading slowly through the

dusted and sprayed vines, and around 10-20 per cent of the melons showed light infection. The sprayed vines appeared to be slightly less heavily infected than the dusted ones. By July 6, nearly all of the unprotected vines were defoliated and dead, while those of the treated plats were still green and growing and reasonably free from anthracnose. Both the dusted and sprayed rows nearest the check plats showed heavier infection of both leaves and melons than those more distant. On July 9, the date of the third picking and ten days after the last application, the untreated plats appeared brown and barren from defoliation and death of vines, and practically all melons were sunburned and poxed. Although the protected vines were still green and growing, anthracnose was at this time beginning to spread rapidly in them, mostly on the new growth that took place after the last application of fungicides. The older vine growth in both the dusted and sprayed plats remained healthy as long as the copper coatings showed on the leaves. From the time of the first appearance of anthracnose in the protected plats, the melons in the check plats showed not only a higher per cent of melons affected with pox, but also a larger number of pox lesions on the melons.
YIELD, CONTROL OF ANTHRACNOSE, AND NET RETURNS IN 1925
The effect of the fungicidal treatments upon yields and the control of anthracnose is indicated in table 7, and on the market value of melons in table 8. A general discussion of those points occurs on page 13.
EXPERIMENT OF 1926
It was demonstrated in the tests of the preceding two years that both the copper-lime dust and Bordeaux mixture were effective in reducing materially the amount of anthracnose in watermelons when applied to rather small plats. Due to the fact, however, that only hand-operated dusters and small dosages of spray mixtures were used, it was felt that the methods and results could not be considered applicable to general field conditions. The third years' experiment was conducted on a more extensive scale, with the object of testing the efficacy and practicability of treating a field under conditions similar to those with which the farmer would be confronted.
METHODS AND MATERIALS
In the 1926 test, a 13.5-acre field of Watson melons on the farm of Homer Williams near Thomasville, was turned
10

over to the writer for experimental use. It contained 58 12-foot rows with hills ten feet apart in the row. An application of 600 pounds per acre of an 8-4-4 (P-N-K) fertilizer was made before planting, and a second one of 400 pounds of 9-2-5 formula at the sides of the ridges just shortly before the middles were plowed out. On May 10, the plants were thinned to one to the hill. While there were very few missing hills at this time, the plants varied considerably in age, some without runners and some with runners a foot long.
The spray rig in use was the :>.arne one described for the two preceding years (page 18). The duster consisted of a two-wheel, mule-drawn Niagara truck-crop duster with a four horse-power gasoline engine, and equipped with two 20-foot light, flexible, metal hoses (figure 6, page 43). The latter were carried by the operators while walking between the rows in much the same manner as the spray hoses and rods were handled. While the plants were young and covered only a minor part of the ground space, the methods of dusting and spraying were similar, consisting of directing the dust pipe or spray nozzle at the individual hills long enough to cover the vines while the operators and machines moved slowly along. As the vines became older, however, and covered the middles of the rows, this "spot" dusting and spraying method was changed to a general sweeping or back-and-forth movement of dust pipe and spray rod. In dusting, it was possible to keep the machine in motion continually while each operator covered the width of two 12-foot rows. In spraying, however, where each operator treated the same number of rows, it was necessary to follow the start-and-stop procedure in order to provide sufficient time to cover properly that width of vines. As the dust stream possessed a longer range of delivery than the spray cone, it was not necessary for the dust operator to walk laterally in the vines nearly so much as the spray operator.
The fungicides used in the 1926 experiment included home-made Bordeaux mixture 3-6-50 for all applications, and a home-made copper-lime dust containing 20 per cent of monohydrated copper sulphate. The dust applications were made in the forenoon after most of the moisture had dried from the vines, or in the late afternoon while the wind was low. The spraying, also, was done during the day on dry vines. The dusted plot comprised 16 rows on one side of the field, the sprayed plot 16 rows on the opposite side, and the unprotected area 26 rows between the treated plots. Data in regard to dates of applications, together with the time required and the amount of materials
11

used, are contained in table 9, page 47, and on the cost of dusting and spraying, in table 10, page 48. There were ten harvests made between July 6 and August 6.
OBSERVATIONS ON ANTHRACNOSE CONTROL IN 1926
Anthracnose was not observed in the field until June 25, a few days prior to the date of the fourth application of fungicides, and ten days later than its first appearance in other commercial fields of that community. About five per cent of the hills in one end of the untreated area showed prominent spotting of the center leaves, with a few scattered affected hills in the rest of the plot. No infection was observed in the treated vines. A week later, leaf infection was common throughout all of the unprotected rows, and by July 6, .one week after the fourth application and the date of the first harvest, 50 per cent of the untreated vines showed anthracnose leaf spot. A few lightly affected hills were found in the dusted and sprayed areas, also.
On July 13, the time of the second harvest and two days prior to the last application of fungicides, the checks showed 60 per cent hill infection, with abundance of recent secondary spread on the younger vine growth. In the areas that developed the disease first, leaf infection was widespread, and all of the foliage in the center of many hills was ehtirely gone. Only slight increase in infection was noticeable in the dusted and sprayed rows. During the second harvest, five per cent of the melons from the untreated rows were poxed. On July 23, the date of the fifth harvest and eight days after the last application, every plant in the untreated area was diseased, and many vines, especially those that were affected earliest, possessed few or no green leaves at all. In such sev3rely affected spots, the melons were ripening prematurely with considerable sunburning. Anthracnose was spreading slowly in the treated plats, and appeared somewhat more prominent in the dusted vines than in the sprayed ones. The unprotected vines were beginning to impart a general browning or burned appearance to that part of the field. The dusted and sprayed plots, on the other hand, were still green.
By July 27, the date of the seventh harvest, the foliage of the untreated vines was almost completely gone from anthracnose, and the disease was spreading rapidly in the recent, unprotected vine growth of the treated plots. The latter areas, however, still appeared green in comparison with the dead, "burned" check plot between them. Only ten per cent of the melons from the treated plots showed anthracnose infection and no sunburning, while 65 per cent of the melons from the unprotected area were poxed and
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20 per cent sunburned. During the last two pullings, practically all of the melons from the untreated plot were classed as unmarketable due to the presence of pox, sunburn, and immaturity. Melons from each treated area showed about 50 per cent pox, but no loss from premature defoliation. From July 25 to August 6, anthracnose spread rapidly in the dust and spray plots on the foliage that grew after the last applications were made, and was responsible for the large number of poxed melons in the last two harvests. Had such a long bearing season and favorable market been anticipated, it no doubt would have been worth while to make an additional application of fungicides.
YIELD, ANTHRACNOSE CONTROL, AND NET RETURNS IN 1926
Outstanding factors that affected the experiment of 1926 were a considerable delay in the set of the first crop of melons, due primarily to rain and wind storms at setting time, a rather late start of anthracnose in the field, a heavy production of large, high-quality melons extending over a relatively long harvest period, favorable weather for the spread of anthracnose, and a fair-to-strong market throughout the shipping season. Data pertaining to yield and anthracnose control occur in table 11, page 48, and on market value of melons and net returns of the crop, in table 12, page 48. The discussion of those subjects, together with the same subjects for the 1924 and 1925 t ests, is included in the following section:
DISCUSSION OF METHODS, OBSERVATIONS, AND RESULTS FOR THE THREE YEARS' WORK
The foregoing subject matter deals principally with the statement of experimental methods and materials, an account of observations made on the behavior of anthracnose in the experimental plats, and tabulated data concerning applications of fungicides, disease control, yields, market value of melons, cost of treatments, etc. The following includes a discussion of the same subjects for the three years'
tests.
EFFECTIVENESS OF THE DUST AND SPRAY TREATMENTS IN ANTHRACNOSE CONTROL
The fungicidal value of both Bordeaux mixture and copper-lime dust was well demonstrated in each of the three seasons. In 1924 and 1925, anthracnose became active early in the history of the field and of the protection program, i. e., between the first and second applications of fungicides,
13

and was widespread in t.he check plats when the fourth application was made. Yet, both the dust and spray not only prevented the general outbreak of the disease that developed in the untreated areas, but also furnished remarkable protection against infection from the adjacent, heavily diseased check plats. Again in 1926, although anthracnose was late in securing a start from the standpoint of both the age of the crop and the status of the protecting program, both kinds of copper fungicides furnished satisfactor,v control, and made possible a long harvest period with unqsually large, high-quality melons. The unprotected area, on the other hand, went down rapidly from the disease once the latter became established. In each year, satisfactory control was obtained as long as the new growth of vines was kept covered.
The control of anthracnose with any of the fungicides appeared relatively more difficult near the end of the season than during earlier periods in the history of the crop. This was especially noticeable in the prevention of melon infection. Each year, the amount of pox increased rapidly during the last harvest or last two harvests. It is believed, however, that this condition resulted not so much from the lack of fungicidal value of materials or of thorough coverage of vines, as from a heavy infection of the new growth of vines that occurred after the last application of spray and dust was made, together with a general washing and otherwise dissemination of spores from the heavily infected check plats to melons of the adjacent treated plats. None of the treatments tested served appreciably to protect directly the melon from pox, especially the underside, in the manner that the foliage was proteeted; and under the circumstances concerned, one might expect heavy poxing of melons in the treated rows even though the fruits were surrounded by comparatively disease-free vines.
It was observed in each of the three vears that Bordeaux mixture spray appeared slightly more effective in preventing anthracnose infection on the foliage, and remained somewhat longer on the vines than the copper-lime dust. The relation between anthracnose control and yield is indicated in table 13, where the total number of melons harvested in each series may be compared with the number of marketable melons. The percentage of marketable melons in the untreated areas for the tests of 1924, 1925 and 1926, was 7.4 per cent, 22.2 per cent, and 49.6 per cent respectively, as compared with 75-80 per cent, 77-81 per cent, and 83 per cent respectively, for the dust and spray treatments. With the heavy loss from anthracnose in the first two years, there was realized an appreciable profit from the
14

use of both Bordeaux mixture and the home-mixed copperlime dust, in spite of the comparatively high cost of protection and low yields (table 14, page 50). The margin of profit from the purchased dust was slight due to the high price of the material. In 1926, even though the loss from anthracnose was less than in the two preceding years, and the market value of the unprotected plot amounted to $109.60 per acre, yet there resulted a decided profit of $89.10 per acre from spraying and of $64.50 from dusting. Those two items of profit exceeded-many times the costs of protection, and the latter were insignificant figures as compared with the loss from anthracnose in the unprotected plot.
In only one instance was there noticed any appreciable difference in the yield of marketable melons in dusted and sprayed plats that might be attributed to a difference in fungicidal value of the materials under comparison. That occurred in 1924 when the per cent of pox in the plats sprayed with Bordeaux mixture containing a spreader and in the dusted plats appeared lower than in those that were treated with plain Bordeaux mixture. During the two years following, however, there was no such indication of the superiority of dust over plain Bordeaux mixture in the prevention of fruit infection. In the 1924 test, where there appeared to be a considerable difference among the different treatments in the total number of melons harvested per acre, and consequently in the number of marketable melons, such difference in fact proved of no significance when the yields of the individual plats were considered. For instance, the plats treated with the commercially mixed copper-lime dust appeared to outyield those treated otherwise (table 3, page 45). The same dust in 1925, however, was associated with a slightly lower yield than the home-made dust.
DUSTING AND SPRAYING MATERIALS
Bordeaux mixture and the copper-lime dust were selected for use at the outset of the project because both had proved their worth on other truck crops, and because both may be prepared on the farm with considerable economy in cost. For the sake of a comparison in fungicidal value, adhering qualities, and other possible features, a commercially mixed copper-lime dust was used in the first two years' tests and a Bordeaux mixture spray formula with a casein spreader, in addition to the dust and spray prepared on the farm. Before the first year's test was completed, it was apparent that a copper-lime dust containing 25 per cent of monohydrated copper sulphate, whether mixed on
15

the farm or prepared commercially, was likely to burn the foliage severely, especially if applied to damp vines. It was learned, also, that a similar dust containing 20 per cent of the monohydrated copper sulphate produced noticeable injury when dusted on wet vines but not on dry vines. A home-mixed dust containing only 15 per cent of the copper salt produced no appreciable injury when dusted on either wet or dry foliage. In view of those observations, the last two dust applications in .the 1924 test were made with the 20-80 formula, 2 and a 20-80 dust was used on comparatively dry vines in the two succeeding years. As the commercially mixed dust manifested no consistent ad"antage in fungicidal value over the home-made dust and was much higher in cost, it was omitted from the expenment in the last year.
It was demonstrated during the first year of the experiment that Bordeaux mixture containing a spreader, although apparently effecting a better spread of the material on the leaves, was only slightly superior to plain Bordeaux mixture in protecting the melon from pox. It produced really satisfactory coverage of exposed parts of the melon onll' when it contained at least three to four pounds of the calcium caseinate to each 100 gallons of material. Since plaln Bordeaux mixture spread well on the foliage, and since it iu primarily leaf protection that insures fruit protection, and! since the addition of the spreader increased the cost of the spray considerably (table 2, page 45), the use thereafter of a spreader was not considered.
Regarding the formula of Bordeaux mixture, it was observed in the experiments of 1924 and 1925 that copper injury occurred on the leaves even though the material for the first two applications contained only three pounds of copper sulphate in each 50 gallons of liquid. In 1926, the formula, 3-6 (hydrated lime) -50 was used in all applications with no appreciable injury noticeable at any time during the season. As melon foliage is highly succeptible to spray injury, and since that strength of Bordeaux mixture not only produced negligible amount of burning, but
furnished satisfactory protection, it is believed that it should be recommended for watermelons generally in the state. The marked spray injury that occurred in 1924 and 1925 might well be attributed to the quantity of materials used as well as the formula, for the rates of application were much higher on the small plats of those tests than in the field experiment of 1926.
2The rate of a s>pllcatlon and the cost of du s t s r e presente<l In tublrs 1 nnd 2 are based upon the 25-75 formula.
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RATE OF APPLICATION OF FUNGICIDES
The proper amount of fungicide to use in each application should, of course, include just enough material to replenish or supplement adequately the coatings of preceding applications. The kind of machinery and the strength of materials in the toxic element are pertinent factors in the rate of applications. In 1924 and 1925, when hand dusters were used, it was necessary to use larger amounts of dusts in order to obtain thorough coverage of vines with the low wind pressure available. In 1924, the rates of application varied from 15 to 80 pounds per acre, with an average of 46 pounds, and the average in 1925 was 55 pounds per acre (tables 1 and 5, pages 39, 42). In 1926, where field conditions were resorted to and a truck-crop duster used with engine-driven fan, good distribution of dust, coverage of vines, and control of anthracnose were obtained with rates of application varying from 13 pounds to 34 pounds per acre, with an average of 22.4 pounds for the five applications. Likewise, in spraying in the 1926 test, satisfactory coverage and protection were secured with an average of 50 gallons per acre for five applications, about half as much material as was used during the first two years where small plats were involved. The rate of spraying was cut down the last year principally by reducing the size of the holes in the nozzle discs, and by closer supervision of the manipulation of the machine as a whole. Men operating spray rods are more likely to duplicate spraying than to shut off the liquid if the machine does not move fast enough for them. It is believed that the rate of application of both dust and spray used in the 1926 test (table 9, page 47), is sufficient to furnish satisfactory control under like conditions if the machines and delivery pipes or rods are correctly manipulated.
TIME, NUMBER, AND FREQUENCY OF APPLICATIONS
The number and frequency of dust or spray applications for the control of watermelon anthracnose will depend upon such factors as the length of the growing and shipping season, the weather conditions prevailing during the particular season, the nature of the general climatic conditions considered over a number of years for the section concerned, and the susceptibility of the crop, all of which factors are known to affect the usual prevalence of the disease in the locality concerned. The time for the first and second applications, it is believed, should be more or less fixed, regardless of weather conditions and the presence or absence of the disease in the crop, i. e., when the plants are beginning to run and from seven to ten days later. Those applications are considered necessary to insure a
17

marked reduction in the amount of the inconspicuous, incipient infection that spreads slowly and more or less unnoticed during the first part of the growing season, but which serves as a source of the epidemic form of the disease that develops usually at or near the beginning .of the shipping period. Where a protection program is to be conducted, it should be taken for granted that at the time of the first application, anthracnose, together with other harmful diseases, is actually already present in the field in its incipient or early and slowly developing stages, merely waiting for proper weather conditions in order to assume epidemic form. Subsequent applications should follow at ten-day to two-week intervals, depending upon how favorable the weather is for the disease, how much anthracnose was present early in the protection program, and whether it is being held in check or not by preceding applications.
The number of applications that should be made, including the length of time that the protection schedule should extend into the shipping season, will depend upon local conditions mentioned above and upon the market. It has been observed in the earliest shipping sections of the state, where normally there occurs an early set of melons with the beginning of a correspondingly early shipping period, four to five applications should furnish adequate control. In seasons with delayed sets of melons, however, or in years with an unusually rainy growing and shipping season, and particularly in the later melon producing sections of the state where shipping ordinarily does not start before the disease becomes epidemic, additional applications will be required. If prospects are at all favorable for heavy anthracnose or downy mildew infection during the shipping period, the dusting or spraying program should extend within a week or ten days of the last harvest, especially if the market is at all favorable.
MACHINERY FOR DUSTING AND SPRAYING
The kind of sprayer or duster for use in the watermelon field may weii be determined by other needs on the same farm. If fruit dusters or sprayers, or machines for treating truck or field crops, are already available, they may be temporarily or permanently altered for use in melons. Since either a good duster or sprayer represents a considerable investment, i. e., around $400.00 or more, the machine might prove more practical if it could be used to advantage on two or more crops on the same farm, or used by two or more joint owners.
Sprayer. Ordinarily, any heavy truck-crop or light orchard sprayer may be equipped to meet the requirements
18

for the melon field. The spray outfit used in these tests (see description on page 11) was employed also in spraying such close row crops as cucumbers, cantaloupes, tomatoes, Irish potatoes, etc. When the machine was to be used in the melon field, the spray boom was merely folded up or removed outright, the short supply hoses attached, and the long melon hoses attached. A lighter outfit consisting of a barrel with double-acting, hand-operated pump, mounted on skids, was tested in watermelons and found entirely inadequate for use in the average or larger fields, except possibly for the first and second applications. Such outfits, capable of developing 50 to 150 pounds pressure under considerable effort, are useful and satisfactory for spraying small acreages of cucumbers, tomatoes, and various other crops, but lack the pump capacity, pressure and the speed necessary in the watermelon field. The pump should be capable of maintaining from 150 to 200 pounds pressure per square inch with three or four leads of hose and twice as many nozzles. The sprayer should be equipped with three hoses if six rows are to be treated, or four hoses for eight rows, with a five or six-foot spray rod on each hose (figure 7, page 43). The nozzles for the rods should be attached with 45 angle connections. It is highly important to have some kind of supports for the hoses in order to prevent them from dragging in the vines, such as long folding arms (figure 8) that extend laterally from each side of the machine when unfolded, or boys to walk and carry them.3
Duster. Hand dusters have !imited possibilities in the watermelon field. The first application of dust, and perhaps the second, in the anthracnose control program may be made to advantage with hand dusters, providing enough are used to cover the field in a reasonably short time. By the time for the second application, however, the vines will be large enough to justify the use of a higher powered duster with a marked saving of both time and material. Although different types of dusters were not available for comparison during the three years' test, the machine with engine-driven fan used in the 1926 teRt and described on page 20 (figure 6, page 43), proved satisfactory for dusting four rows. One essential feature in effecting a good job of dusting in melons, or any other vegetable or fruit crop so far tested, is a forceful blast of wind strong enough not only to furnish distance or range in operation but also to disperse or distribute the material thoroughly. The machine re-
3For full suggestions and Illustrations regarding practical and proper kinds of equipment for s prnying watermelons, together with convenient types of 1pray mixing and filling stations, It Is recommended that r eference be made to U. S. D. A. D e t>t. Circ. 90, 1920, and to U. S. D. A . Fa.rmers' Bull. 1277, 192%.
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ferred to furnished sufficient air volume and pressure for two 2%-inch pipes in dusting four 12-foot rows. While walking continually, the operators directed the dust both to the front and the sides (figure 9, page 44). The limit of effective working distance included from four to six yards on each side of the operator, depending upon the amount and direction of wind, with an average total width of around ten yards, or approximately three 10-foot rows, for each pipe. Since the growers ordinarily turn the vines at every sixth or eighth middle for driveways during harvest, it would perhaps be more practical to dust six or eight rows at one time. For a field of 12-foot rows, this would require more fan power than the duster used in 1926 could furnish, in order to supply three distributing pipes of the size mentioned above or two larger pipes.
Demonstration of dusters and dusting attachments. In 1927 and 1928, three different makes of orchard dusters, such as are used on pecans in the state, were operated in melon fields for the purpose of demonstrating the adaptability of such machines fitted with various types of delivery pipes for melon dusting. It was observed that the largest and heaviest orchard dusters are relatively light and convenient to handle in melon fields, as compared with ordinary heavy types of truck-crop sprayers or light weight orchard sprayers with tank capacity of from 150 to 200 gallons. In determining possible working distances and promising distributing systems, single, double, and triple outlet connections were tested. Each machine was equipped with a larger fan and engine than those on the crop duster used in 1926. Where eight to ten horse-power engines furnished the fan power, it was possible to cover the vines for a width of from four to five 10-foot rows on each side of the duster, depending upon ihe amount and direction of the wind, merely by waving slowly the single, short orchard pipe from side to side as the team walked along. This width of field would be equivalent to about seven to nine 12-foot rows. In trials where the same machines were equipped with two short, three-inch pipes attached to a Y connection, and with the operator standing on the duster platform, a total width of five to six 10-foot rows or four to five 12-foot rows was satisfactorily covered at a faster rate of operation than with the use of the single pipe. When the three-inch pipes were extended and carried by operators while walking between the rows, each operator was able to cover approximately four 10-foot rows by dust-
ing to the front and sides, or three 12-foot rows. When
there were three three-inch pipes attached, there was suf-
ficient air force from each pipe to take care of three 10-foot
20

....
rows or two 12-foot rows, as the operators walked slowly through the field.
One marked handicap in dusting with the long flexible pipes is the necessity for the operators to walk into their dust clouds resulting from directing the pipes forward and to the sides (figure 9, page 44). This is especially noticeable if the wind is blowing in the same direction in which the machine is moving. It was for that reason that demonstrations were made with operators standing on the machine and directing the dust to the sides and rear with short flexible pipes. This method was found more practical later in the season when the vines covered the ground. Earlier. when the plants were small, it involved a waste of material. When the operators carried the long pipes between the rows, they were able to accomplish a much better job of dusting individual hills with a minimum waste of material. With such equipment, it is advisable to have high boom arms or standards attached to the machine to support the pipes, or to have them carried. It seems that it would be practical under the growers' conditions to use the long flexible hoses or pipes for the first two or three applications, and the short pipe attachment with operators standing or sitting on the machine later when the vines covered the middles and when there would be danger of injuring the plants by walking between the rows.
In the operation of all types of dusters in the melon field, there was observed one outstanding factor that affected markedly the coverage of vines, namely, the fact that the dust adhered to and covered effectively only those leaves that were within range of the direct air blast of the fan. This fact was observed repeatedly in the 1926 experiment and again in the demonstrations with orchard dusters. The slowly drifting dust cloud, although hanging low over the field, is of little value in furnishing coverage to the vines.
The principle demonstrating the value of a forceful air blast in dusting melons and the insignificance of the drift cloud, was well illustrated again in a cooperat ive demonstration4 in a melon field in 1928. The machine possessed a large fan driven by a four-cylinder motor, and was capable of delivering a tremendous blast of air through a short, flattened outlet more or less fixed in position. During the demonstration, the machine was pulled slowly but continually through the field, and the dust cloud drifted low over the vines for a distance of at least two hundred
4Thts du s ting d e mons tration was c onduc t e d in COOJ)era.tion with l\lr. F . C. Meier, Exte nsion Phnt Pathologist, U . S . D . A ., \l'as hlngton, D . C., and the Shunk l\la nufa cturlng Company , Bucyrus, Ohio. It was arrange d by 1\lr. i\Iel e r, and conducted in a Jn e lon fl e Jd n cnr B aconton. ~litch ell County, Ge org ia.
21

yards. Although there was but a trace of wind and the vines were wet with dew, yet close observation after the vines had dried revealed prominent coating of the foliage only in the vicinity of the machine where the leaves were stirred by the direct draft from the fan. Such a method with a continuous discharge of dust through a fixed pipe would no doubt prove wasteful of material, for it was found in that case that, with a moderate rate of feed of dust, the latter was used at the rate of 100 pounds per acre for one application.
Traction types of dusters, in which the fan power is taken from the wheels, were not tested in melon fields. If there are such machines that are capable of creating sufficient air volume and pressure to cover thoroughly the vines of four to six rows while the machine moves slowly, there appears to be no reason why such dusters would not be still more practical for the average grower than machines with engine-driven fans.
TIME REQUIRED FOR DUSTING AND SPRAYING WATERMELONS
The time required for dusting and spraying melons in 1924 and 1925 was much greater than in 1926, due to the use of hand dusters and small, short plats for both dusting and spraying during the first two years (tables 1, 5, 9, pages 45, 46, 47). For example, in 1924, it took two men with hand dusters 13 hours to dust an acre of melons seven times, or an average of about 1.8 hours for one application, and an average of 1.6 hours in the 1925 test. In 1926, on the other hand, where the dusting outfit consisted of a field duster with three men and two mules, it required only 61 minutes to mix and apply dust for five applications, with an average of about 12 minutes for one application. In spraying an acre of melons in 1924 and 1925, it took three men and two mules an average of 60 mjnutes and 56 minutes, respectively, for the two years, to make one application. In 1926, the same outfit covered an acre in the average time of 26 minutes per application, including all steps in the spraying operation, slightly more than twice the time for dusting an acre.
EFFECT OF WIND AND LEAF MOISTURE ON SPRAYING
AND DUSTING
Spraying of melons may be done throughout the day with a light to moderate wind prevailing, but should be done while the vines are dry in order to insure maximum coverage and adhesion of the fungicide. Dusting possesses more limitation in regard to the effect of wind on the operation.
22

While a good job of dusting may be done during a light wind, yet a moderate or strong wind usually interferes greatly with distribution of the dust. For that reason, it has been found advisable to confine dusting to the early forenoon and late afternoon, unless, of course, the wind should be low during the remainder of the day also. While it was learned that wet foliage will retain more dust than dry vines, yet there are two important reasons why the growers should not dust wet vines. In the first place, the 20-80 copper-lime dust recommended for dusting dry vines is very likely to produce appreciable injury if applied to damp vines; and in the second place, the operators are more likely to spread disease by walking through wet vines than they are to control them by dusting under such conditions. Yet, if the dusting operation may be done without disturbing the plants at all, as for instance by walking between the rows when the runners are still short or by manipulating the discharge pipes from the duster platform, then it would be safe to dust the field while the vines are wet; but, the weaker strength of dust, the 15-85 formula, should in that case be used. It is well to remember, however, that watermelon vines, due to the highly pubescent condition, will retain sufficient dust of the 20-80 formula to furnish adequate control when perfectly dry.
INJURIOUS EFFECTS FROM DUSTING AND SPRAYING
The foliage of many plants is subject to chemical inJury, or "burning," when certain copper fungicides are sprayed or dusted upon them, the degree of injury depending upon the copper content of the material, the ease with which the copper is converted into the water-soluble form, the amount of fungicide present on the leaves, and the susceptibility of the particular plant to that type of injury. Cucurbits generally are quite susceptible to this type of injury, which is referred to as "spray burn," "copper burn," etc., and which is commonly attributed to the penetration of soluble copper salts into the leaf. Although there is definite evidence pointing to the amount and strength-in-copper of the dust or spray as being important factors contributing to that kind of injury, yet it has been observed that some kinds of weather conditions also may function in that respect. In watermelons, this form of injury is first recognized by a definite fading out of the green color along the margin of the leaves. That tissue may turn brown or black and dry up, in case it dies. Light cases of marginal burning have been observed to recover more or less completely. Where such injury persists from one application to the next, a stunting of the entire plant occurs, often resulting
23

in small set and size of melons. It is believed that permanent injury may result from the use of Bordeaux mixture containing more than three pounds of copper sulphate to 50 gallons, if used as often as it should be to insure satisfactory protection. A corresponding condition applies for the use of a 20-80 copper-lime dust for dry vines or a 15-85 dust for wet plants.
There is indication of another type of injury which may result from copper dusts and sprays on watermelons, i. e., a slight delay in the first setting of fruit, which, of course, results in a corresponding delay in maturity of the crop. This condition was noticed in 1924 and 1926, but not in 1925. In the first year's test, the first two harvests from the untreated plats comprised 20 per cent of the total yield of those plats; from the plain Bordeaux mixture plats, 15.2 per cent; and from the home-made dust plats, 15.7 per cent. In 1925, the first harvest amounted to 59 per cent, 57 per cent, and 59 per cent for the untreated, sprayed, and dusted plats, respectively. In 1926, the percentage of the total number of melons in the first two harvests was 25 per cent, 17 per cent, and 16.5 per cent for the untreated, sprayed, and dusted plats, respectively. In 1924 and 1926, the difference in the size of melons, also, in the treated and untreated areas just prior to and during the first harvest, was quite noticeable as one walked through the field. The reason for such injury is not known, but may be due to a direct interference in pollination or to a disturbing of the vines at the time of the first setting of melons.
A third type of injury that may occur, but not from the direct effect of the fungicides, is a knocking off or bruising of melons and bruising of vines by the dust and spray operators as they walk through the field. This kind of injury, which may easily be reduced to a minimum with a reasonable amount of care, is almost unavoidable if there is a heavy growth of vines, especially in the case of rows ten feet apart or closer. Still another possible and probable means of injuring the melon crop during dusting or spraying, is the spreading of anthracnose and other diseases by walking through the field while the plants are wet. This danger has already been referred to in the discussion of dust and spray applications.
COST OF DUSTING AND SPRAYING WATERMELONS
The cost of protecting a melon crop by either dusting or spraying will no doubt vary considerably on different farms, depending largely upon the kind of equipment, whether or not the machine is to be used solely for melons, the system of labor, and the cost of spray or dust materials.
24

In general, the cost of materials in the dusting of any crop constitutes a greater item in total cost of protection than in spraying the crop. Dusting, on the other hand, is generally much faster and requires less equipment, including men and mules. The total cost really should take into account the purchase price and depreciation of machinery, together with water pumping facilities and supply wagons or trucks necessary in spraying, dust mixing devices, etc. Although spray materials are usually less expensive than dusts, yet good sprayers ordinarily cost more than dusters with corresponding working capacities, and the cost of additional time, man and mule labor, together with the extra pumping and hauling equipment, no doubt raise the total cost of spraying to a figure approaching that for dusting.
In the first two years' tests, when small plats and hand dusters were used, and when a spreader and different formulas of fungicides were tested, the total cost for treating melons depended largely upon the amount and cost of the materials, and should not receive serious consideration in the application of methods and results to practical conditions. Methods and equipment used in the 1926 test, on the other hand, together with the cost of dusting and spraying, might well be applied to the growers' conditions. It will be noted from the data in table 10, that the total cost of dusting an acre five times with a home-made dust of the 20-80 formula, where the ingredients were purchased in small lots, was $5.90, including labor and materials only. The cost of the dust included $4.80 for materials and 10 cents for mixing, per hundred pounds. At the present time, various companies are offering their commercially mixed 20-80 copper-lime dusts for $6.00 to $7.00 per hundred pounds. At such cost rates, the dusting program in 1926 would have cost around $7.10 to $8.25 per acre instead of $5.90 with the home-made material.
In the case of spraying, where no additional equipment for mixing and refilling was used, due to the close proximity of field to pump station and to the method of making Bordeaux mixture, the five applications of 3-6-50 spray cost $2.70 per acre, including only the cost of materials and labor. In spraying melons, the cost of materials and of labor were just about the same, while in dusting the labor item for both mixing and applying the dust amounted to less than 10 per cent of the two combined. If the cost of motor gas and oil, extra equipment and labor required ordinarily in spraying, and estimated depreciation of machinery be added to the costs mentioned above, then the total cost per acre of five applications would be close to $7.25 for dusting with the home-made 20-80 dust, $5.30 for spraying
25

with 3-6-50 Bordeaux mixture, and from $8.45 to $9.60 for dusting with commercially mixed dusts.
PROFIT IN DUSTING AND SPRAYING MELONS AGAINST ANTHRACNOSE
The melon grower would expect to secure a definite profit from protecting his crop, even though it amounted to no more than an absolute insurance against the average amount of disease losses that occur in his section, or against the possible heavier or maximum losses that might be experienced. The principal factors that affect profit or loss from protecting melon fields with fungicides in any given season, are the following: The amount of loss from diseases that ordinarily occur in the section concerned, the cost of the protection program, the yield and market price of melons, and the degree of control secured by the dust or spray treatment.
In the 1924 and 1925 tests, even where hand dusters and small plats were involved, appreciable net profits were realized after deducting the relatively heavy cost of the treatments and comparing the net return with the sales value of the unprotected melons (table 14, page 50). The net profit for spraying in those years was $29.92 and $47.52 per acre, respectively, compared with $15.70 and $35.40 for 8usting with the home-made copper-lime dust. Although the actual market value of the melons, after deducting losses from anthracnose, was about the same for the two kinds of treatment (tables 4, 8, pages 46, 47), the difference in the cost of dusting and spraying during those years gave a greater net profit for the spraying operation. In 1926, with the use of a field duster, the cost of dusting did not affect so seriously the amount of net returns and' profit. That year, when loss from anthracnose was comparatively light, but when an unusually heavy yield of melons was produced and the cost of protection relatively low, a marked profit was obtained from both dusting and spraying (table 4, page 46). The net profit for spraying amounted to $89.10 per acre, and $64.50 for dusting, in spite of the fact that the untreated plot brought an average of $109.60 per acre. Although the degree of anthracnose control was about the same in the two methods of protection, as indicated by the amount of loss in market value from anthracnose in the two cases (table 12, page 48), yet there remained a difference in net profit of $24.60 in favor of spraying. This difference, however, is not wholly accounted for by the greater cost of dusting (table 10, page 48), which exceeded the cost of spraying by only $3.20 per acre, but mostly by the greater yield of melons in the sprayed plot (table 11, page 48) due to the difference in soil type, terrain, and drainage on the two sides of the field.
26

APPLICATION OF METHODS AND RESULTS TO GROWERS' CONDITIONS

RELATION OF METHODS IN GROWING AND MARKETING MELONS TO ANTHRACNOSE LOSSES AND CROP PROTECTION

There are several factors that determine to what extent

the methods and results of the experiments in the control

of watermelon anthracnose, and reported here, may be ap-

plied to the growers' conditions. It is not the desire to

recommend dusting or spraying to any melon grower un-

less the program might prove practical and profitable. First,

let us consider some conditions that exist generally in the

production and marketing of melons in the state before

citing those factors.

.In the first place, a crop of melons is not a very expen-

sive one to produce. The selling price or gross returns,

however, is ordinarily subject to a great many disturbing

factors, such as a general overproduction with light demand

resulting in low prices; a flooding of the market during the

most favorable time of the shipping season due to simul-

taneous, heavy movements from states and sections that or-

dinarily do not ship heavily at the same time, or due to in-

discriminate methods of selling; poor stands with light

yield, a late set of melons, or generally low quality melons,

all due to adverse weather conditions; and finally a reduc-

tion in quantity and quality of melons due to anthracnose

and other field diseases. Under average conditions extend-

ing over a number of years, the margin of profit for water-

melons is found to be never very great. In years when

there is an overlapping of two or more of those conditions

mentioned, there may occur generally little or no profit at

all, but a decided deficit instead. Any unusual or additional

item of cost in production then might mean a further re-

duction in profit; or, if it causes an increase in either quan-

tity or quality or both, it perhaps might bring about a de-

cided increase in profit.



In regard to the effect of quality on the value of the

melon crop, one person of authority says "Watermelons

unlike most other vegetables are a cheap commodity and if

quality is poor they become so cheap that they will not

sell for enough to defray transportation costs. . . . This

week hundreds of cars of melons have sold for less than

freight charges in various markets of the country ....

not because there was no demand for melons but simply

because the dealers could not afford to invest the enormous

amount of freight charges in melons that because of quality

27

could not be sold."5 That situation resulted from a generally heavy movement of low quality melons. This low quality might be caused, as stated above, by unfavorable growing conditions, such as excess or deficiency of rainfall, field diseases including anthracnose, or by transit conditions. Most of the transit troubles, however, are due to diseases that have their origin in the field, as anthracnose decay and stemend rot.
In the second place, once production of the melon is accomplished, the marketing of the crop presents an important problem for the grower. It is the ambition of every grower, whether independent or organized, to bring his crop to maturity as early as possible for two reasons: First, because prices at the outset of the shipping season are generally higher; and second, in order to escape losses from anthracnose and other field diseases that usually become most destructive during the latter half of the shipping period. Many growers, especially those in the earliest shipping sections of the state, are able to get the majority of their crop on the market before diseases become epidemic. The majority, however, particularly those in the later melon sections, have the latter part of their shipping season cut short due to premature defoliation and to poxing of melons. This condition is still more likely to occur in years when the melon crop is late. It is a common occurrence, also, during such seasons for a high per cent of the melons that are loaded for good quality and sold for high prices, even though showing little or no pox at loading time, to go down in transit due to anthracnose decay which had its origin in the field (figure 5, page 42). So that, although the grower who sells for cash to the track buyer may escape to a large extent the direct effect of anthracnose, some one is going to be the loser, and the loss is marked down as due to quality. In such cases, the losers ordinarily include buyers and dealers who guarantee freight charges, bonding companies who make the same guarantee, or the growers themselves if consigning their own melons, and the railroads. Growers or shippers who consign melons to distant markets, soon realize the intimate relation that exists between losses in transit from field diseases, prevailing freight rates as compared with the intrinsic value of the commodity, and probable profit or loss.
FACTORS AFFECTING THE ADVISABILITY OF PROTECTING MELONS AGAINST ANTHRACNOSE
In referring again to the factors that might determine the practicability of dusting or spraying for anthracnose
5S OWEGA Stamlard Vol. 6, ~o. 5, 1928.
28

and other field diseases, they might be stated as follows: The average margin of profit the grower realizes for comparatively disease free melons, the cost of treating the field with dust or spray, the yield and prevailing market prices of melons, and the customary amount of loss that occurs in his section from diseases that may be controlled by the treatment. If in the case of watermelons, or any other crop for that matter, the usual margin of profit is small for high quality products and the amount of loss from diseases is generally low, then there would be no argument for an additional cost in production. On the other hand, even though the margin of profit may be relatively small and considering that the average loss from diseases is considerable, the probability is that protection of the crop, if not too high an item of cost as compared with the remainder of the overhead cost of production, would be profitable. In fact, under such conditions, the high average loss from diseases ordinarily is one factor that keeps the margin of profit so close by reducing both yield and quality of the crop.
APPLICATION OF A SPECIFIC EXAMPLE
In applying the above analysis to the melon situation in Georgia, we find the following ~tory which might be said to fit the average conditions. Many cases will of course fall outside the provision.
Consider a melon crop in south or middle Georgia of twenty acres. It has been variously estimated that the cost of producing an acre of watermelons amounts to around $25.00 to $40.00, and of loading a car around $20.00 to $35.00. Considering a yield of one car to two acres of melons for a favorable growing season with little or no loss from diseases that may be controlled by protecting the field, the total cost of production and delivery would be around $75.00 to $115.00 per car, or $37.50 to $57.50 per acre. At this rate, and considering an average gross receipt per car of $150.00, the gross returns per acre would amount to around $75.00 with a net profit of from $17.50 to $37.50. But if we consider the loss from anthracnose and other field diseases that may be controlled largely by dusting or spraying, then the returns drop off by 30 per cent, amounting to about $52.50 instead of $75.00, and the margin of profit falls to $5.50 to $15.00 per acre. Taking for granted that 85 per cent of the 30 per cent loss could be prevented by spraying or dusting six times at a cost of $6.40 to $9.00 per acre, respectively, based on the cost of dusting and spraying in 1926, then the net returns would
29

amount to around $8.00 to $25.00 per acre, a gain from treating the vines of $10.00 to $13.00 per acre.
If the above analysis is applied for a year with a loss of about 20 per cent from preventable field diseases, then it is found that the cost of protection is just about the same as the loss from diseases. Records indicate that losses to the growers from anthracnose alone before shipping vary from 10-60 per cent, with an average of 30-35 per cent; that losses from other field diseases vary from 5-25 per cent along with or independent of anthracnose; and that ordinarily losses from anthracnose to shippers and dealers may equal that realized by the grower. Although it may be said that it would not pay the grower to treat his melons where losses from field diseases are 20 per cent or less, yet it should be remembered that with such a treatment costing only about $6.40 to $9.00 per acre, the crop may be insured against the average loss of 30-35 per cent of the gross returns due to anthracnose alone, and that the losses from preventable diseases rarely fall lower than 20 per cent and often reach 40-50 per cent or more. Then, there is little or no reason to assume that the value of the commodity would not soon go up due to an increase in quality, especially if enough growers would practice protection to attract the discriminating eye of the buyers, dealers, and consumers. This assumption would no doubt be doubly strengthened if at the same time the problem of marketing melons were adequately controlled to prevent indiscriminate selling which results in the flooding and demoralizing of markets. Marketing methods usually determine whether it is quality or quantity that sets the price of a commodity, regardless of the general demand for the product. Records of present day successful producing and marketing organizations in both fruits and vegetables bear that out.
The question for the melon grower might be put as follows: Is $6.40 to $9.00 per acre too great an additional item in production when it would insure the crop against one of the principal factors that reduce yield and quality and which alone is responsible for an average loss of 30-35 per cent of his crop? Each grower should apply the question to his own case. The matter might have an altogether different application for the small grower whose melon acreage constitutes a comparatively minor part of his total crop acreage and money invested, and for the larger grower who, year after year, plants a considerable acreage, invests heavily in it in space of land, fertilizer, and cultivation, and depends upon that crop as his chief, or at least one of his chief farm resources. In the first case, the cost of the protection program, including the initial investment in rna-
30

chinery and other necessary equipment, might prove relatively high when compared with the remainder of the production costs and with the net returns of the crop. In the case of the larger grower, however, the cost of the protection program would in all probability be insignificant when compared with the other overhead costs or with the net returns of the crop.
RECOMMENDATIONS FOR ANTHRACNOSE
CONTROL
It is the firm belief that melon growers of the state will profit materially in escaping losses from anthracnose and other common vine-blighting and fruit-rotting diseases if the following suggestions, exclusively of the last one named, are observed. Furthermore, those growers whose methods of growing and marketing melons will justify the additional expense of treating the field properly with a fungicide, will no doubt find the additional recommendation of protection a safe investment of insurance against losses from anthracnose and other field and transit diseases, and perhaps a means of decided profit besides.
PRACTICES OTHER THAN PROTECTION
Field selection and rotation. Use a field that has not been in melons or cucumbers for at least five years, or better ten years for avoiding Fusarium wilt, because the organisms causing anthracnose and other harmful diseases are able to live for long periods in the soil. Select a field that does not receive drainage water from land that has been in melons within that period, and one that has free air and water drainage.
Time of planting. Plant as early as possible and replant freely in order to bring the crop to maturity before diseases become widespread and destructive.
Seed selection. Save seed only from perfectly shaped melons of high quality that are cut from the vine, preferably early in the maturing season, at least before diseases become general.
Seed disinfection. Treat the seed before planting, preferably just after saving and while still wet, by soaking them for five minutes only in a solution of mercuric chloride (corrosive sublimate) prepared by dissolving that material in water at the rate of one ounce to eight gallons. Stir constantly during the treatment, then wash in three or four changes of clean water, drain well, and spread out to dry. Use only wooden, earthenware, or glass containers for the
31

disinfectant, and dissolve the material in a little hot water before diluting. Cold water may be used if drug store tablets are employed in making the solution. Place the treated seed in clean bags.
Fielcl sanitation. Avoid disturbing the vines at any time during the growing season while they are wet. Particular times for observing this precaution are during thinning, hoeing, plowing, pruning, turning runners for roadways, spraying and dusting, and above all, during harvesting. While the germs of some of the melon diseases are spread primarily by wind, others, including those of anthracnose, are scattered almost altogether by the splattering effect of rain, surface drainage water, and by objects moving through the vines while the latter are wet. Observations over a number of years indicate that more damage is done to the crop through spreading diseases during harvest than during all the rest of the operations combined, merely by cutting the melons from the vines, "toting" them to the roadways, and loading them into wagons or trucks, while the vines and melons are wet (figure 5, page 42). The harvest period is the natural time for diseases to become widespread or epidemic, and any tendency that might favor the spread of the organisms should be avoided. In this connection, it is recommended that melons be cut from the vines either in the early forenoon after the vines are thoroughly dry, or in the late afternoon of the day preceding loading, and not during the early morning while the vines are wet from dew or during rains. In either case, a long stem should be left and then recut at the car before applying the stem-end treatment; or, in case of cutting the melons in the late afternoon, the stem-end paste might well be applied both in the field and again after loading in the car. It is believed that much more harm many result due to premature defoliation, poxed melons at loading time, and decay in transit, from cutting melons from the vines and hauling them from the field while they are wet, than from what ill effects that might result from leaving pulled melons in the roadways of the field over night.
FIELD PROTECTION WITH DUST OR SPRAY
It has been demonstrated that the protection of watermelons with dust and spray fungicides was not only effective against common diseases, but practical as welL Furthermore, under some conditions of crop production, it will no doubt prove profitable. For the grower who believes he can afford to spend an additional item of around $6.40 to $9.00 per acre in production costs in order to insure his
32

crop against losses from anthracnose and other destructive field diseases amounting to 30-35 per cent, on the average, the following recommendations are furnished.
Method to use, dusting or spraying. One method is not recommended above the other. Both are effective in crop protection and practical. It may depend entirely upon the grower, or perhaps upon the kind of machinery he may already have on the farm. It is suggested that reference be made to the description of the duster and sprayer used in the 1926 experiment, and the discussion of machinery in the general discussion of methods, observations and results. For the average grower who would have to invest in new machinery for treating the watermelon field, it might be said that dusting is perhaps easier, faster, and almost as effective as, and generally more adaptable or practical than spraying.
Machinery to use. Any spray outfit that can feasibly be operated in a melon field, with a pump capacity of at least ten gallons per minute and capable of maintaining a pressure of from 150-200 pounds per square inch while delivering liquid to six spray nozzles, is satisfactory. Truck-crop sprayers with triplex pump and gasoline engine, or light orchard sprayers are well adapted for this use. The duster should be of sufficient size to carry from 50-100 pounds of dust and to create enough wind pressure and volume to blow the dust out forcibly through one four- or five-inch pipe, two three-inch pipes, or three 2%,-inch pipes and to insure thorough coverage of vines for a distance of three or four rows on each side of the machine. Hand-operated dusters and sprayers might be used to advantage in the first application while the plants are small, and perhaps in the second, but not in subsequent ones. Again, note description and discussion of machinery referred to in above paragraph.
Materials to use. For the spray formula, use home-made Bordeaux mixture which is the cheapest and perhaps most effective spray material available. The formula 3-6-50, that is three pounds of copper sulphate, six pounds of hydrated lime, and 50 gallons of water, or more accurately, enough water to make 50 gallons of spray. The lime should be a good grade of hydrated or builder's lime, preferably with a high calcium and low magnesium content. If the grower knows how to slake stone lime properly, and wishes to assume the extra time and trouble to use that form of lime, he should use 4% pounds per 50 gallons instead of six pounds of hydrated lime.
Preparation of Bordeaux mixture. The spray material may be prepared as follows: Suspend over night enough
33

blue vitriol (copper sulphate) in a burlap bag in a barrel of water to make one pound of that material to each gallon of solution. It is advisable to measure the barrel first and mark the inside of the container at the level of the 25-gallon and 50-gallon lines, then run in water to within five or ten gallons of the volume needed for the amount of copper sulphate weighed out. After the salt is dissolved, remove the bag and add enough water to reach the level of the marker. Start filling the spray tank with water, and at the same time weigh out enough lime for six pounds for each fifty gallons capacity of the spray tank. Add enough water to the lime in a lard can or small barrel to wet the material thoroughly and permit ready pouring. Careful mixing with a paddle will be necessary in order to get the lime into suspension. When the tank is about two-thirds full of water, start the agitator and pour in the lime through a strainer, then add the proper amount of the stock solution of blue vitriol to make three pounds of that material to each fifty gallons of tank capacity. Finish filling the spray tank. The spray may be prepared in a supply tank in that manner and hauled to the field and there drained or pumped into the spray tank.
Copper-lime dust and its preparation. The dusting material for watermelons should consist of twenty parts of monohydrated copper sulphate, i. e., the partly dehydrated, powdered form of blue vitriol, and eighty parts of hydrated lime. This is the formula for dusting dry or nearly dry vines. If the dusting equipment is such that damp vines may be dusted without the necessity of walking through them, then the amount of monohydrated copper sulphate should be reduced to 15 per cent and the lime raised to 85 per cent. Either formula is obtainable at several places in the state, and such dusts are referred to as 20-80 and 15-85 copper-lime dusts.
The same materials may be prepared on the farm by mixing thoroughly those two ingredients in various kinds of patented dust mixers, or in home-made mixers. Melon growers in other states6 have secured good results in using concrete mixers, old insecticide drums, and other improvised equipment. Probably the most practical mixer consists of an insecticide drum with a few medium-sized rocks inside and a tight lid, placed between the runners of a sled and held in place by two cross pieces just far enough apart to allow the drum to roll freely between them. The ingredients are weighed out in the correct proportion and placed in the drum, and are then mixed by pulling the sled over
6J eble , R. A., a nd S. F . Potts . Dus tin g nnd s pray ing canta loupes. 1\la r y lnnd Agrlc . Exp. Stn. Bull. 263 , 1924.
34

rather rough or uneven ground. Other types of rotary mixers may be made in which the drum is mounted on standards and turned by a crank. Thorough mixing is necessary for effective results. Ordinarily, such dusts may be mixed for one-half to two-thirds the cost of purchased dusts of like contents.
When to spray or dust. Spraying should be done always on dry vines, hence during the day after the dew has dried. In dusting, if the method calls for walking through the vines as in spraying, this operation also should be done while the plants are dry and always while the wind is low, preferably during the early forenoon and late afternoon. If the duster equipment is such that it is not necessary to disturb the vines while dusting, then the operation might well begin in the early morning in order to take advantage of low wind conditions, even though the vines are wet. In this event, however, the 15-85 dust should be used as long as the vines are wet.
Make the first application of dust or spray when the plants are beginning to run, preferably not later than when the runners are a foot in length. The second one should follow from seven to ten days later, and subsequent ones at ten-day to two-week intervals, depending on weather conditions, the amount of diseases in the field, etc. The last application should be no later than the beginning of the shipping period. Under average conditions, protection might well extend to within a week or ten days of the last cutting, thus requiring from five to seven applications.
How to spray and dust. In spraying melons, it is customary for the operator to walk between the rows he is spraying, waving the spray rod back and forth; or, during the first and second applications, to direct the spray at individual hills of the two rows. In dusting with two or three extended flexible pipes, similar procedure may be followed. For .further suggestions, however, reference should be made to the description of machines and methods in the 1926 experiment and to the general discussion of those subjects. The principal point to be observed in either dusting or spraying is the importance of insuring thorough distribution of the fungicide and coverage of both the upper and lower sides of the leaves without undue duplication.
Precautions in dusting and spraying watermelons. Do not use spray material after it has stood in the tank over night or otherwise long enough to allow settling of the suspension to the bottom of the tank. Be sure you have a good grade of lime for either operation, and that the dust is thoroughly mixed. If you are not sure of thorough mixing, it will be far better to purchase the dust already mixed even though
35

it costs more. Do not spray in a strong wind or dust in a moderately strong wind, for material will be wasted with a poor coverage of vines. In the mixing and application of dusts, wear a respirator that covers both the nose and mouth. Same may be procured at local stores. Do not allow either the dust or spray to accumulate or remain long on the skin, for it will irritate or probably prove poisonous. It is easily removed by washing in a weak acid solution, such as vinegar, lemon or other citrus juices. Do not use spray pump pressure less than 150 pounds per square inch; 200 pounds is still better. In dusting, do not depend upon coverage farther away from the machine than the distance where the air blast and dust stir the leaves; or, in other words, do not depend upon "drift" dusting to furnish protection, for it will not. Disturb the vines as little as possible throughout the season, and never walk or drive through them when they are wet. Keep the runners trained away from the r oadways by turning them from time to time during the season.
SUMMARY
During the three years of experimental dusting and spraying, watermelon anthracnose was controlled appreciably with from five to seven applications of a copper-lime dust containing 20 per cent of monohydrated copper sulphate for dusting dry vines or 15 per cent for wet foliage, and Bordeaux mixture 3-6 (hydrated lime) -50, with a minimum amount of injury to the foliage. Bordeaux mixture furnished slightly more protection to the foliage than the dust, but the degree of pox control on the fruits was practically the same in the two methods of treatment. There occurred no appreciable difference in the control of anthracnose on either foliage or melons from the use of homemade and commercially mixed copper-lime dusts of the same formula, but the home-mixed material was made for almost half the cost of the purchased dust. The number of prominently poxed melons was reduced by the dust and liquid treatments in 1924 from 82.9 per cent for the untreated vines to 20-25 per cent; in 1925, from 74.3 per cent to 19-27 per cent; and in 1926, from 48.3 per cent to 16.5-17 per cent. Both dust and spray completely prevented losses in the form of immature and sunburned melons due to premature defoliation from anthracnose, as compared with 70.1 per cent, 25 per cent, and 24.3 per cent damage in the untreated plats in 1924, 1925, and 1926 respectively.
The use of hand dusters, while satisfactory for the first, and perhaps the second, application, proved entirely inade-
36

quate for the entire schedule due principally to waste of time and materials and to the difficulty in making prompt, timely applications. A two-wheel truck-crop sprayer and duster, on the other hand, with gas engine-operated pump and fan, proved not only efficient in distribution of materials and coverage of vines, but practical as well. Satisfactory coverage and protection of foliage were secured in dusting; only when the plants were close enough to the machine to be stirred by the direct wind force from the fan, and not by drifting, low-hanging dust clouds. The most practical methods of delivering the dust to the melon vines with the minimum amount of injury to the vines, consisted in men carrying extended flexible pipes while walking between the rows they treated, i. e., before the vines were old enough to meet in the middles, and in standing on the platform at the rear of the duster while manipulating one or more short, flexible pipes after the vines were old enough to overgrow the middles. In the case of spraying, it was found both advisable and necessary for each operator to walk between the two rows he treated, using a spray rod fitted with one or two nozzles.
With the equipment employed in 1926, with no elaborate spray mixing station or refilling or supply tanks, it was possible to spray an acre one time in about 26 minutes, and to dust an acre in about 12 minutes, including time for mixing, hauling, and applying the materials, i. e., considering the average time for the five applications.
The cost of dusting an acre of melons in 1926, under field conditions, amounted to $5.90 for five applications, i. e., including the cost of materials and labor only. In spraying, the cost of materials and labor amounted to $2.70. It is estimated, however, that if all items of cost were included, such as depreciation of machinery, grease and fuel, maintenance of spray pumping, mixing, and refilling facilities, and dust mixing devices, the cost of five applications of dust and spray would approach $7.25 and $5.30, respectively; and, in the case of six applications, $9.00 for dusting and $6.40 for spraying.
The profit derived from protecting watermelons against anthracnose depends primarily upon the amount of loss from that disease in untreated fields in the particular section and season concerned, the yield and market price of melons, the degree of control secured with the treatment, and the cost of the protection program. An appreciable profit was realized in all three years of the experiment where the home-made fungicides were concerned. The cost of dusting with the purchased dust, costing 10 cents per pound, in 1924, on the other hand, was almost as great as
37

the loss from anthracnose, even though there occurred an unusually heavy loss from that disease in the untreated plot.
Several types of injury that may result from dusting and spraying watermelons are recognized and discussed, including chemical injury, or copper burning of the foliage, interference with the early setting of fruit, bruising of melons and vines from walking through them, and the spreading of anthracnose in the field if the operators pass through the vines while the latter are wet.
In attempting to apply the methods and results of dusting and spraying watermelons to the growers' conditions, several factors are discussed that appear to determine whether or not vine protection will prove practical and profitable, such as the acreage of and the amount of money invested in melons, the ordinary amount of losses from anthracnose and other field diseases in the sections concerned, the average yield and selling price of melons there, and the cost of a protection program. The average or larger grower whose losses from such field diseases as anthracnose and downy mildew are 20 per cent or more, could in all probability afford to protect his crop year after year with dust or spray.
Recommendations are included for means of preventing losses from anthracnose and other diseases, exclusive of as well as including the protection of the crop with fungicides.
38

t' IGURE I. TyJticnl anthracnose infection of watermelon leaf. These spots furnish s pores thnt are was hed or carri e d to other lea l"es. nnd to th e m e lon itself r es ulting in the .,pox" stage of th e di seu se. (See fi g ur e 3a, b .)
39

:nGURE 2. Advance<l stage of u.nthrac~ nos e on wate rmelon leu.f which results In trentature defoliation nnd denth of ,lnes.
40

(n )
(b ) F IG UR E 3. Fruit Infection b y w a.ter1n e lon a n t hracnose. or 0 Jl Ox ''; a, di stribute d o ve r entire &nrftLce of y oung frui t (11.bout one-fourth g rown ); b , t y Jli cal infection on underside of tna ture m elon.
41

FIGURE 4. Close view (naturaJ s ize) of pox lesions on the nte lon of figure 3b. The central pn.rt of each 1na.t ure l esion co n s i sts of n. ]link nut ss or laye r of SJJOres. This s tnge of th e di sea se ofte n r es ults In th e ty1> e of loss ln<ll cn.tetl In llgure 5.
F I GU RE 5. S c ,e r e los s from anthra c nose infection of w att' rm e lou;;;; , or rw x . th at d evel OJl Cd cluring t h tj trnn s H ru:- rl o d . Thi s tyJ) C of loss ofte n r es ult s frorn c uttin g n:telons front h envll y di seased \'ines durin g a rnln or while th o Yln e;;;; and 1ne lons are w et front d e w, es p cc i aH ~ if tra n sit co nditi o n s u r e c~ ondud, e to the d eve lopme nt of a.nthrncnose dccny. A lthoug h pox was not lli scernible on these ntelons when they were Jlln ced in th e car, th e load wu s a. totul loss 11110 11 n.rrlvnl ut its d estln a.tlo n du e to infection thnt occ urre d in th e field s hortl y bet'ore or durin g har, est. P rotection of ' 11nf'S with du st or SJlrn y r e duces tran ~ i t losses to a nliniJnurn . (Courtesy of SO\\"J1:;GA ~f e l o n G-:o w e rs ' :\ S!i'ocintlon, .t\cl e l. Geo r gia.)
42

FIG UR E 6. Gasoline engine-power t ruck c rop dus ter u sed in t h e 1926 t est, with boom removed a nd two long , fl exible, m e tal pipes attach e d fo r dusting waterme lons. Al though the p ip es a r e li g ht In w e ig h t, the y should b e SUI>Ported b y standa rds or uprig hts on the du ster f ra rne, o r carried b y s on1oo ne in orde r to prevent dragging In the vines.
F IGUR E 7, Two-wheel truck c r01> SJ>rayer e quiJ>pe d wit h four lend s of hose a nd s pray rods. The b.lg h cleara n ce of s pray tank a nd a xle Is ofte n d esira ble on acco un t of the common occurre nce of stumJJS Ln m e lon field s on n e wl y clea red la nd . (From U. S. D. A. D ept. Circ. 90, 1920.)
43

FIGURE 8. Four-wheel, ligh t -we ight orc ha.rtl s pray e r J>TOJ> Crl y e quipp e d for s praying wn.termelons. The home -n1n.de arms SUJ>J>Ort the long ltoses u sed in SJ>ray lng rows at the s id es of the ma chine. 'Vhen these boom s nrc folded, ordlnttr y cl ea.rn.n ce of the m.nchine Is sec ured for drhrlng through gntcs nn(l doors. (F rom U. S. D. A . Dept. Clrc . 90, 1!120.)
FIGURE 9. The tl u ster u setl In the 1926 a nthrac nose control ex p e riJne nt In action. 1' h e li g h t, fl exi ble pipes are ea s ily ma.nlpulate d , but s hou]tl b e s upporte d b y a boom ur by s omeo n e car r y ing then1. R es .-lrntors co,re rln g both mouth and no se o r e necessar y in this operation.
44

Table 1. Dates of spray and dust applications in 1924, together with
the time required and the quantity of materials per acre used for each.

Date of appli ca-
tion .
May 16 27
June 10 17 27
July 8 17

., ::;pra y No. 1.

_-:~>.,,_., " "0:::

"...' ~
~r ;:::
I = ::: c-:; ::.-""Q':) ..-

35

25

50

40

90

4-0

125

50

160

45

125

40

115

40

Spra y No. 2.

"g' , ".,",.._

~]
0:::

~G..).'.e.-=g=.

35

25

50

35

90

40

125

50

160

45

120

40

120

35

Dust No. 1.

""="'.,;
o"' ",'

"""r- ~ ' = .~::g=~

:l.::>

Hr-.::.

15

25

20

35

35

90

60

125

80

180

60

150

50

145

Dust No. 2.

1"o""")"''.",""~.'

""..".' ~ ,: =.= G) '-
-H- rC~ -".:-.:.....

12

25

15

35

40

95

65

130

75

180

65

150

55

145

Spray No. 1: 3-6-oO Boru eaux mixture for fir s t two applicatlons, anu 4-G-50 for r em ainuer. Spray No.2: 4-6-'h (Kayso) -50 for first aJ?plication, and 4-6-1-50 for remainuer. Dust No. 1 : Hom e- mixed 25-75 copper-lime dust for first five application s, and 20-80 dust for la st two application s. Du s t No. 2: 25- 75 copperlime ou st purc hased already mixed.

Table 2. Data relative to the cost of spraying and dusting waterm elons seven times in 1924, calculated on a one-acre basis

Spray and dust treatments.

""0)
~ ""'
~05"=i:',~g-o~o
o Q.) -=
<a~~j~8~=&

Bordeaux mixture 3-6*-50, 4-6-50

700

Bordeaux mixture plus Kayso , 4-6-1-50 700

Copper-lime dust, home-mixed,

20-80, 25-75

320

Copper-lime dust, pu rchased, 25-75

327

Refers to hydrated lim e.

Cost ($) of:

o00;
;::
B
...:-l.

""o'"o"et:o.

~t:o=

~ c">.

..=o..:'QJ-8Q0,..

5
0 f.;

4.65 4.20 8.85 7.50 4.10 11.60

18.40 32.70

3.60 22.00 3.30 36.00

Table 3. Data on yields and anthracnose control in the watermelon spraying and dusting experiment of 1924.

S11rar anu du st treatm ents.
Plain Bordeaux mixture Bordeaux mixture
plus Kayso Copper-lime dust,
home-mixed Copper-lime dust, purchased Check (no treatment)

2

-'""'e""~' .

a. ~

:::: oot;

-O Qj

.5.=!
o lll

~?'

~=-=

590

625

580 638 608

...., "-~tol':o/:1:.-u:G:"s):..:.r.t:SJ..
::: ~rec ~a;:~
~o.a~ 27.5
27.4
26.7 26.0 29.6*

:::.
....,~
~~
~a~ ~r.i:cn .... s:,.!J::
';;0()
I Q) ll.J
88 :0 15.4
18.0
19.3 18.00 18.7

X 0 .::::~.......:.
~::: =Q~.I-
-~"o~':8."o-."o"~-'
~ Q.,...,
25 .1
20.8
21.3 20.0 82.9

Q w ~~
s =~~ ~
~.;~:Q~)8~~~
f;Z~a..:=
~"s' ",.c.a.o-~
0.s-=.:0.~."~0
None
None
None None
70 .1

Including m elon s of marke table s ize on ly, i.e., 18 pounu s anu o ,e r.

45

Table 4.

Data regarding market value of melons, loss from anthracnose, and net returns, in the spraying and dusting experiment of 1924.
Loss(%) in market value due to:

P lat tteatments.

Plain Bordeaux

mixture

383 74.50 15.7 22.9 43.83 34.98

Bordeaux mixture

plus Kayso

406 78.95 17.2 15.6 53.05 41.48

Copper-lime dust,

home-made

368 65.43 18.2 16.4 42.76 20.76

Copper-lime dust,

purchased

418 68.45 17.9 15.3 45.76

9.76

Check

(no treatment) 45 73.60 19.4 73.7

5.06

5.06

*Based upon net prices received by the SOWEG.A. l\Ielon Grower s' Association for melons of corresponding sizes and dates of picking, disregarding the effec ts of anthracnose and undesirable shaped melons.

Table 5. Dates of spray and dust applications, together with the time required and amount of materials per acre used in each, in the 1925 melon anthracnose control experiment.

Date of applications.
May 18 25
June 6 13 20 29

Bord eaux mixture IHome-mad e copp e r - ~ Purchased copper-

4-8-50, 3-6-50.

lime-du st 20-80

lim e-du. t 20-80

Gallon s I used

Time r equired. Pounds (minute ~) u se d

Time required. Pounds (minutes \ used

Time r equired. (minutes)

35

20

16

45

15

45

85 95

I 25

35

35

55

70

35

110

55

70 105

130

40

60

105

60

110

130 150

I 45

80

50

80

95

80

115

80

95 115

Table 6. Data regarding the cost of spraying and dusting watermelons six times in 1925, calculated on a one-acre basis.

Spray and dust treatments.
Bordeaux mixture 3-6-50, 4-8-50 Copper-lime dust 20-80, home made Copper-lime dust 20-80, purchased

...,,,;
=';.,_.::l
o., ~-;;
;:~!:oro o Q) =~:~
.a.:~a"S'&"
625 326 325

....;
.;s::
4.""2""'8
15.65 26.00

Cost ($) of:

'0 ... <l OOl~
.o.~..._b~l)_~ <l
..c,_.:.",'
..:la ..
3.30 2.47 2.35

'5
0
E-<
7.58 18.12 28.35

46

Table 7. Data on yields and anthracnose control in the watermelon spraying and dusting experiment of 1925.

P lat treatments.
Bordeaux mixture 3-6-50, 4-850 Copper-lime dust 20-80, home-made Copper-lime dust 20-80, purchased Check (no treatment)

... "'.;:,
::: oo ":3
;5 ~ ~
~~ ~ ~
...,:. 8 '-.q...
~0~~
411 432 420 414

..,

.:: .t~.:.D. c0cn~rQo'>....0C:b..
~~ ~ ;

to8
>~

... ca

c0 .

<l o .<l ~

28 .9 28.5 28.6 28.8

"'.., 0
.QP. ~
. .J;~ ;:* ~
"o"'e"-"o"'
4> ~ oo
:2~
19.0 22.9 27.1 74 .3

...:.
. *a~
":::o'-"o
tL""-oz
_o0c0 .'a"0,>o-I-::
~4>.0~"~0
None None None 22 .0

Table 8. Data relative to loss from anth r acnose, market value of melons, and net returns of the crop, in the spraying and dusting experim ent of 1925.

l'lat t reatments.

Bordeaux mixture 3-6-50, 4-8-50
Copper-lime dust 20-80, home-made
C