G- A 
A~oo. L:: 5 Q. \ 
I'\D ,~ I 
 
Georgia State Board of Entomology 
E. LEE WORSHAM. State Entomologist. Atlanta. Ga. 
 
CIRCU LAR 21 
 
FEBRUARY 1917 
 
EXPERIMENTAL 
DUSTING AND SPRAYING OF PEAGHES 
BY 
\V. \V. CHASE, 
Assistant Entomologist 
 
ATLANTA - 
 
- GEORG IA 
 
 GEORGIA STATE BOARD OF ENTOMOLOG Y 
ORGANIZATIO N 
HO~. .T.J. BR O\ rf\, Cha ir man, Comm iss ione r of Ag r icultu re , At la nta . 
nON. H. C. BERCIC\ fAN S , A ug usta. 
HO N. Jf\O. A . COBB, A me r icus. 
E . LEE , YOR S H AM, S ta te Entomologi st and Se cr eta ry of th e Boa rd , A tl anta . 
A. C. Ll<JWIS, A ssistant Stat e E n tomo logis t, A t la nta . 
, Y. V. REED, A ssi stant E nto mo log ist, A tla nta . 
, V. ' V. CH A S l<;, 
Assi stant En tomo logist , Atlanta . ,Y. F . T URXER, 
A ssis ta nt E ntomo log is t, 'I'h oma sv ille. 
IR A ' V. , YI LLI A"JI S, 
A ssis tant in Cotton B re ed ing, Atla nta . C. A. ~I cLEND ON, 
Expert in Cotton Breed ing, Atla nta . .J. D. S "JIIT I-I, 
Assista nt Entomologist , Valdosta. C. G. CR I T 'eE NDE f\ , 
A ssis ta nt in Cha r ge Tran smissi on of Cott on Dis ea ses by Insect s, 'I'h oma svil le. 
 
 EXPERIMENTAL 
DUSTING AND SPRAYING OF PEACHES 
BY 
W. W. CHASE 
I N T R O D U C T O RY. 
The aim of this circular is briefly t o r eport on th e r esults thus far obta ined in cer t ain peach du sting expe riments und ertaken and conducted by th e Georg ia State Bo ard of Entomology. While these expe r iments ha ve not been pr oductive of conclusive r esults th ey have indicate d st rongly th e possibility of the success ful and profitable adapta tion of du sting to commercial peach and apple productio n. Th e data obtained are cer t ain to be of inter est to progressive or chardi st s, fo r such men a re always in a r eceptive attitude t oward innovations t ha t promise great er effic iency and bigger pr ofits. 
Some apple du sting ha s also been don e in this State. B ut, as th ese t est s wer e limited to only one season (1916), and, as circ ums ta nces di d not permit th e harves t ing of th e du sted ap ples at maturity, no compre hensive r esults were obtained . I n the following pages dusting is treated only in r ela ti on t o peaches. 
Results of th re e seaso ns' expe r iments mu st be considere d as ve ry encouraging. P a rti cularly is this true of th e three sp ecific objects in vi ew-control of (1 ) peach curc ulio, (2 ) peac h scab and (3) brown r ot. Coincident al with in sect and disease contro l, however, a marked d emerit of du sting manifest ed it self in th e t end ency of th e du st to defoliate trees and t o split, or cr ack, the peaches. This is not a fund am ental fault, it a ppears, and would seem to be eas ily av oidable. Owing t o th e pure ly expe rimenta l nature of th e work, mist ak es were 
of ma de in th e excess ive quantity of material applied and 
in th e method of application. Most th e foli age an d fruit injury noted in th e tests , while somewhat influ enced by weather conditions, is th erefore attribut able to overdosa ge of dust. R esponsibility for this typ e of in jury would seem to belong more to the exp erimenter and hi s mistakes th an to oth er cau ses. 
Plans are laid for th e continuation and extens ion of th e work with a vi ew to th e prevention of this single oh- 
3 
 
 j ectionable feature, without, at th e same time, detra cting from the efficie ncy of th e r esults. 
I-IISTOHY OF DUS'rI:KG IN GEORGIA . 
Th e present s eries of experiment s is not th e fir st work of it s kind in this State. A s far ba ck a s 1906, before the advent of se lf-boiled lim e-sulphur solution, Xlr. A. C. Le wis , of th is department, in expe r ime nts located at W ell st on , used a mixture of p u lveri zed B ordeaux an d sla ked lim e fo r th e contro l of bro wn r ot of pea ches. Th ese expe r ime nts were dupli cated and amplified th e fo llowing year by th e writer a t ?llayfield . Th e material s us ed in th ese tests were of th e cr udest hom e-made manufacture. They were of coars e in echanicn I texture and, being mixed with a shovel, necessarily were irregular in com position chemically and volumetrically. 'I'he applicatio n was made by means of a hand-pow er dusting rnachine , entire ly inadequate to th e purpose. Detail s of manufacture and application will be omitted. Th e principal r esult of this ear lier dusting work, h owever, wa s to demonstrate the unsuitability of drv B ordeaux mixture and kindred mixtures to th e du sting of f oliated pe ach trees. Invariably almost total destruction of th e foliage ensued, with total or partial loss of th e attendant cr op of peaches. All of whi ch dis couragem ent ca used a temporary abandonment of dry sp raying experim ents. 
Interest in dusting was r evived in 1913 and experiments with an entirely new mixture and with imp r oved machinery were undertaken , The fir st of this se r ies wa s located at Adairsvill e. Following a se ve re hail storm in ea r ly Ma y of tha t year, which pra cti call y r uine d th e en ti re cr op of fruit in t hat sec tion, bu t one application wa s made before it becam e n ecessary t o abandon the te st a s originally planned. In 1914, th e location of th e work wa s r emoved to Cor ne lia wh ere it ha s since been prosecuted annually. 
CO~IPOSITION OF DUS'r MIXTUHES. 
Dus t mixtures, as used in th e test s und er cons ide rat ion, are composed of two active elemen ts -superfine ly groun d sulp hu r an d powdered arsenate of lead. S ulphur, whi ch ha s an es ta blished fungicida l valu e, acts as 
4 
 
 a preventative or antidote of orchard tre e di seases, and arsenate of lead is perhaps th e best and best kn own stomach poison used in th e supp r ession of insect pests that chew their food. In addition to these two active antidotes, sulphur and lead a rsenate, two of the mix ture s test ed in cluded a th ird ingredient, hydrated lime, which served merely as a filler . Hydrated lime, being- che np and eas ily available, was add ed to th e sulphur and lead; both compar atively cost ly, t o r edu ce th e cost of the mixh u e. 
Th e sulphur and arsenate of lead cons tit uting- th o straig-ht sulphur-l ead mixture used are so finely g-round that practica lly 100 per cent. of it will pa ss a 200 mesh scr een. Much of it is even finer. The two a re tho ro ughly mixed and in corpor ated, one with the other, in a mix ingmac hine especially desig-ned for t he purpose, so that fo r any g-iven sample of ma terial th e r atio of sulph ur t o ~ead and of lead to sulphur is precisely the same . In the t ests of 1915 and 1916 thi s ratio wa s !15 parts su lphur to 5 pa r ts lead arsenate. In t he t est of 1914 this ratio 
"Was no to 10, bu t it wa s found that ]0 per cen t. of lead 
arsenate wa s more than is actually r equired su ccessfully to contr ol eurculio, so that th e per centage of lead was r edu ced to five in subs eque nt te st s. Sulph ur-lead-lime mixh u es of two fo rm ula s were used, one a 4570 sulphur, 50/0 lead, 50'10' lime composition and th e other a 600/0 sulph ur, 50/0 lead, 35'/0 lime. Th e addition of these qua ntities of hydrat ed lime ma kes a mixture of smoother phy sical texture than sulphur and lead ar sena te alone. It is more fluid, and th e t end ency to lump, as evidenced in the sulphur-l ead mixture, is obviated. 
For th ese mixtures it may be said that all claims advanced for th eir fineness are well founded. Due to th eir impal pable t exture they will search out and coa t,' when p roper ly applied, all pa rts of a t ree . T hus, in a few second s, it is possible to secur e a unif or m and tho ro ugh distri bution of material through out a dense tree top. Such thoroug-hness and un iformity, in the enve lopment of fo liage and fruit with a combined fungicide and in secti cide, is re latively impossible of attainm ent "With liquid sprays, excep t by th e expenditure of much g-reater tim e, labor and material. Compar isons of th e two methods are r educed, therefore , to two elementary cons ide r ations -; effic iency and cost. 
5 
 
 APPLICATION. 
Th e material was applied in every exp eriment with a mot or-driven" Ideal" du st er, manufactured by the Kansas City Du st Sprayer Manufacturing Co., of Kansas City, Xlo. This outfit, mounted and equipped with a 2 1/~ horse-power "New ",Vay" air-cool ed gas engine, is shown on Plate 1. It ha s a capacity, when fully loaded, . of about. 100 p ounds of material. Additional material, sufficient to la st for half a day's du sting, can r eadily be carried in sacks on the bed of the wagon. The dust is fe el through a valve at th e bottom, cone-shaped end of th e hopper, falls into an iron pipe and is forced out through th e spout attached to the iron pipe by a strong current of air gen er ated by the fan . A canvas-covere d elbow joint gives more, or less fl exibility to th e pipe or spout by mean s of whi ch th e du st is direct ed on to the t r ees. 
Severa1 f eatures of thi s outfit are open to criticism. It do es not always giv e a uniform output; the material is not screened through th e bottom of th e hopper, as it should be, and th e fan does not impart eno ug h " drive" to th e dust to meet all r equirements. 
Th ere are smaller outfits for dusting on a small er scale, but on an ext ensive scale only th e pow er-driven dusters are ad equate. 
Dusting is done from the windward side of the trees and the dust smok e is carried through th e trees and awa y from the op erators and t eam. Thus there is a cumulative building-up of du st particles on th e leaves and fruit of a number of rows to leeward. Plate III illustrates th e drift of th e dust smoke through sever al rows of trees behind th e row to whi ch th e du st is bein g dir ectly -applied, 
Du sting is-or should be-continuous. It is not only unnecessary, but po sitively wasteful and injurious, to st op at ea ch tree, exce pt wh ere trees are excep tiona lly large, to apply material. It ha s been demonstrated in these expe r iment s that very heavy applications of mat erial do not appreciabl y enhan ce th e degree of insect an d di sease control, but do tend to defoliate trees and to cr ack fruit in the manner illustrated on Plate IV. 
Du e to its finen ess of division, th e du st adheres well to leaves and fruit. It might be sus pecte d that th e fir st 
6 
 
 rain would wash all evidence of it fr om th e tree, but this is not th e case. F ollowing a r ain, an appli cation of dust shows more plainly on leav es and fruit than it does immediately after application. 
Dusting may be <lon e at an y tim e that it is not raining or too windy. .A light wind ste adily blowing in one direction makes th e- best conditions. Moisture on the tree when spraying is not n ecessary to catch and hold th e du st particles. They adh ere well to dry leaf surfa ces and espe cially to th e fuzz y skin of th e peach. 
RESULTS. 
In Tabl es 1, 2 and :J detail ed data on th e control of pea ch scab, curculio and brown rot are given. The tabl es also in clude the number and percentages of cr acked fruit in each plat. These figures were obtained by pi cking and class ifying th e fruit of sever al r epresentative trees from each plat as the peaches ripened. 
In th e test summar ized in 'I'abl e 1 th e dust mixture cau sed a great deal of cr acking, or checking, of th e flesh of th e fruit, amounting, in the plat du st ed three tim es, to ;36 per cent. and in that dusted four times to 49.5 per cent. .A pa r adoxical r esult of th e t est, doubtles s du e to th e continu ous dry weather, was that in neither du sted plat wa s th er e the slightest defoliation. Th e leaves of the dusted trees were the greenest and healthiest of any in th e entire spr aying sch edule. Brown rot infections en te re d five pel' cent. of th e cr a cked fruit in one instance and fift een pel' cent. in th e oth er. Th e r emainder, although s plit and checke d, wa s dry and hard, and carried' well wh en ship ped. Both th e du st ed plats r eceiv ed in- 
ordinately heavy dosa ges 0' du st at every application, 
and to this fact may be attributed the large percentage of cracked fruit. .A II flesh-ch ecked fruits, othe r wise unbl emished, are coun te d as sound. Adjoining plats were treated with th e st andar d 8-8-50 self-boiled lime- sulphur solution, atomic sulphur and pa st e sulphur, r espectively. Th e la st named wa s nothing more or less than the same grade and quality of supe r fine sulphur used in th e dust mixtures worked into a thick, h eavy paste with water. In th e spray tank it wa s, of cour se, pure, finely ground sulphur in snspension. Arsenate of lead in a powdered form was added to the first and sec ond spr ayings and omitted from th e third. Only powdered arsenate of lead was used in thi s and succee ding experiment s. 
7 
 
 Table 1. Classification of Picked Elbertas (1914) . 
 
~ Iat Spraying I 2ndSpraying , 3d Spraying ' spr~~ng --"""~\n",",,_-,,~ ~~"n:.1a"~""" --"~~_ 1~ i~_.~_.: 
 
---1- -1--1-----1\-:----- _ _ 
 
I 
 
Num- Per- l:\ ulll- Per- :\um-1Pl'r- !:\ulll-'\"p cr- Xu ru-lP er- ~ g 0.- 
h e r ! lO'lut l lx-r 1 ce nt h er l l'cnt I her ce nt ber \ ce n t ~ e, -0::: 
 
1 ILead arsena-;-.Self-boil~l ime-:- - - - - - - - - - - - -- 'I- -'- - -I- - I- - 
 
l lb., lime 3Ib"., su lphur and ~/:2lbSe lf- bo i led lime- 
 
wat er 50 gallons lead arsenate __'sulphur S-S-50 i 
 
2 
 
Lead ?-rsel,U1.te li b., lime 3Ibs., 
 
I ,: tt om :;)Ibs., 
 
i~ce 
 
asdu 
 
I 
lphu. rl:ttom ;1lh., albs., 
 
ic su lp 
wat er 
 
h 
 
~l rI; so 
 
water 50 gallons water ;)O g:l llons . l~all ol1s _. . . 
 
' __. 
 
I 
 
,I 
 
. __ _ 8t2'99.7 2 I 0.2 __ J . _J _. _, - - 3 0.3, 844 99 
 
. 
 
I 
 
i 
 
'I I'I 
 
I' I I 
 
, I _ _ _I 
. _ 12liI I\)1.1 2;) 1.\) 
 
i _,I ! 4 0.3 fi\) ;) ..3.1290 \)0 
 
I 
 
I 
 
' 
 
3 Lead ?-n.;.en~te 
 
Waste sulphur 10 
 
. 
 
ilbs., lead arsen-Ipaste sulphur 10 
 
: .: 
 
Ii 
 
,""limn> .---_..','_.--_.. . li b., It:ne 3 1bs., late ;1lb., water.lbs., w a t e I' 50 
4 ~::::~o ~:'~I:nTO gallons , - _.. . 
 
! 
:1005 90.3 4\ :1.7 .. - 
 
t.-.-- , 
I 
 
I1 
 
. 
 
I 
 
I 
 
. 
 
115 
 
10 
1 
 
.4 
 
111001'" 
 
1t91U00l~%e - 
 
sUlphur~ .I i 
 
lead. m Ix - I , 
 
.' 
 
Same as fir st, 
 
- - - - - - - - - - s amp as hn;t.. . _:uu l secon d 
 
1, 
 
,I 
 
_ ,r . _ 
 
r: 
 
'! 
 
102\)4.1139 a .2 _. . 1_ .. , 
 
II 
 
. I" 
 
_ 
 
. _:2bS ,{h.l 14190 
 
5 
 
\Dust 90 % 
 
esdulwphituh~'- 
 
: 
I 
 
10% lead mix- I", 
 
Sa me 
 
as 
 
first~ ~a m e 
 
, 
I 
as 
 
i 
I 
I 
 
ii 
 
. 
 
I 
I 
 
!I 
 
II i 
I ' ; _. 
 
-1- ~:::~~- - -- - -  - - I~ame as firSk _ 1and second ,fil'.';t three_1 3G4;S5 04 14.9 - - - - - ~ - ~ - -1212 149.a 428 
 
6 (unsprayed) ICheck 
- 
 
Check 
 
I 
 
-I270,28.(ijlG 1.0 1 ' 0.1,G/ 3 ,09.71 _ --l- - _ 9649 0 
 
180 
 
 D LTSTIl\G OUT F IT AND OI'EHATO HS 
 
 D Uf;Tl NU If; AN EAf; Y AND lUPID r ou 
 
 A LITTLE \\'1 :\'D FA VOH S T liOHO UGli Dl ST Hl B UTlON OF ~I AT E lU A L 
 
 PLATE I' "l'YI'I(' .,1. ,, 1'1.1"1'"1' 1:\( : 1'1l11I>UC ED BY DO" l :\( ; T OO Il E A'I I. Y 
 
 Table 2. Classification of Picked Elbertas (1915). 
======-==-===-:-c-:=:=========~ 
 
1st Spraying 
 
2nd Spraying 
 
3d Spraying 
 
Sound 
1 
 
II 
 
'Brown Hot C u rcu Jio Scab be d 
 
Sp iit 
 
1 
 
1- - - - - - '- - - - :- - 
 
_ ~ .~s. ~~~ 
;; ~ 2 ~c; 
 
~______ 
 
_ 
 
l"UIUher 
 
I:})ceern- t 
 
!N um- 
I her 
 
Perce nt 
 
\NUm- Pcr- 
her I cent 
 
NUm-l\p erher ce nt 
 
N um-Per- 
her I cen t 
 
.:.J g 
t""'lf=-l 
 
~~ 5o.~ 
 
- - ,- - j- - -- - - ,- -- - - -1- - -- - - - -1-I-L-e-a.-d a-r-se-n-a-te- I-72- -1S--e-If-b-o-i-le-d- li-m-e'--- iSelf-boiled lime- 
 
i--- lbs., lime 3Ibs., wa- sulphu.r and 72lb. lIsulPhur 8-8-50 1018 86.61_ -- 
 
11 0.9'15113 4' 0.3 1181 98 
 
I I I tel' 50 gallons lead at senate, ____ 
 
2 Lead ~rsel1ate 172 Self-boiled li~e- iSelf-boi.led li~ne- 
 
I 
 
I 
 
Ibs., lime 3Ibs., wa- sulphur and 72lb. sulphu r 8-8-.)0 _.. __ GHl 98.4 _ __ ___ ___ ___ 10 1.5 5 0.8 629 99 
 
tel' 50 gallons lead ar senate _ 
 
3 Lead .arsAnat e 172Atomic sulphur Atom ic sulphur 4 
 
Ibs., lime 3Ibs., wa-14Ibs., lead arsenatelbs., wat er 50 gals. 749 98.2 __ _ ___ 3 
 
t el' 50 gallons--- - - 72lb., water 50 gal. 
 
I! 
 
10 1.3 51 6.7 762 99 
 
i I 4 
 
LIb~~a. ,dlI. mar:se3nIbaste., 
tel , 50 gallons 
 
l,72IPaste sulphur 10 Past e sulphur 10 
" a-I bs., lead arsen atelbs., wat er 50 gab . 721b ., water 50gal. 
 
! 
 
I: 
 
491 
 
92.2 _ I 
 
__I___ 
 
5 9le5a%d arssuelnphatuer ,d5u%st- Same as first 
 
NTo ne 
 
1041 ;_).6 --- 
 
3 
 
38 7.1 51 9.G 532 96 
 
6 0.5 41 3.7 92 8.4 1088 99 
 
I 6 95% sulphur, 5% Is ame as first. - - - - iSame as first and 
 
\9b.1\ lead arsenate dust, 
 
second 
 
l 63 
 
l19 _ 
 
1 
8 1.2 2 0.3 22 3.3 196129 .5 6G3 77 
 
7 45% sulp}~ur, 5% Same as first lead, 50% lime dust 
 
!s amc as first and 
 
' ?: 
 
lsecond - 
 
l 
I 
 
993 
 
90._:_-- 
 
43 4 64 5.8 421" 3.8 1100 90 
 
8 Check (unsprayed) Check 
 
Chec k 
 
\ 905 185.3\ _ 
1 
 
57 5.3j 1091iO.2 11 0. 1 i 1 80 
 
 Th e most conspicuou s it em of Tabl e 2, whi ch sets forth the condense d statis tics of th e test of 1915, is again th e fruit-ch ecking and splitting r esulting f rom three applicat ions of sulphur-lead mixture. Th is injury, whi ch wa s gene r al over th e entire plat and may be considere d as r epresented by th e figures in Tabl e 2, was accompanied by a heavy defoliation. Th e trees wer e so badly denuded by mid summ er that an ap plication of tw o p ounds of nit r ate of soda was mad e to each tree in or der to offset th e devitalizin g effects of defol iati on. Th e heavy loss of leav es wa s an unprecedented and un exp ect ed development. Overdosage wa s one contr ibuti ng cause, for th e erro r , commit te d in ] 914, of st op ping at each tree and a pp lying a heavy blanket of dust at close range, wa s ag ain made. But th e most important fa ctor influencing th e r esults, in combination with th e excess ive amount of material used, was r ainfall. Almo st imm edi at ely after each application wa s mad e th e trees wer e wet by sharp summer showers , altern ating with hot sunshine . Th e moisture and heat stimulated the chemical action of the du st ingredi ents upon both folia ge and fruit and cause d th e extens ive burnin g and defoliation. 
In Plat 5, whi ch wa s du st ed only twi ce, defoliation did not r each such advanced stages, although it was marked. Th e fruit of thi s plat, it sh ould be noted in passin g, was more brilliantl y colore d than that pr oduced in any other plat of th e entire test. It wa s as near perfect as it is possible to produce peaches. 
Th e sca b infection s, in all sa ve th e untreated check plat, wer e few and obscure. All peaches ca rrying even one scab in sp ecti on spot are classified as scabb ed. Commer ciall y, however, pra cti cally all of th e peaches list ed as scabbed were p erfectl y sound and sala ble. 
Another notabl e feature of thi s ta ble is that th ere wa s not a sing le rot-infected pe ach in an y of th e plats with th e excep tion of eight split peaches in P la t 8. 
Th e for mulas of th e self-boiled lim e-sulphur solutions used in th e spr ay ing of Plats 1 and 2 wer e id entical except that in Plat 2 th e solution was made with superfinely ground sulphur like that used in the du st mixtures. No material diff er ence in r esults was obt ained, one netting practi call y th e same good re sults as th e oth er. 
Th e sulphur-lead-lime mixture in thi s t est did n ot yi eld 811r11 goo d scab cont r ol as th e straight sulphur -lead mix- 
10 
 
 ture. The infection sp ots were individually lar ger and more numerous . The hi gher percentage of eurculio infes t ation in this plat is a ccounted for, partly, at least, by th e n ear proximity of a body of woods to th e plat. The liability to infestation in th is block of trees wou ld have been g re ate r in an y cas e. 
 
Tabl e 3. Classificati on of Pi cked..E.. lbertas from Dusted Pl at s (1916) . 
 
I I - - Treatm ent 
 
.. :c I 
 
~'! " 
 
8=" - " .- i Sound Brown Rot 
:-;rum- ~ INum-IPer- be r cent! b er dent 
 
C ur cu li o N um~P~ 
b cr ce nt ---- 
 
Sc a b be d !\um ':-P er- 
~~;-= 
 
S p li t N Um-jPCr - 
:~~~~ 
 
~ 
 
'" 
~~0" .~"d" 
 
",,"~ ~ 
0 ... .>1 
~~:a ~8 
 
1 Th ree spray- 
.u.. iunlgas1w._i_th__F_o_r_m__- 
 
! 
3 1 3. G 110 1:1.8 38 4 .4 860 98 
 
2 F irs t a nd sec -, ond with For m- 
ul a 1. t h i r d wit h 1 ormula 2 29 5 
 
3 Th r e e spra y - 
 
i F 
 
n gs orm u 
 
la 
 
w2 
 
i__t_h_ 
 
957 
 
4 Fi r s t w ith Formul a 1, sec on d and t h ir d with F ormul a 2 95 0 
 
5 T h r e e sprayuinl gas w3 i_th__F_o_r_m__- 375 
 
6 C heek ( u n - 
s pr ay ed) -- - -- 8 6 
 
I 
 
1----- 38.b I 
 
- - -- - 322 
 
78 1__ - - - 
 
12 
 
I 
! 
 
79 - - -. - -- -- - . 26 
 
vs --- -- - - -- - 15 
 
12 2H \ 
 
4 G28 
 
42 .4 279 36.7 0 .9 26 1 2 1.2 
2.1 235 19 .5 3 132 25.6 88 59 4 83 
 
18 2.3 i 59 75 14 1.1 1227 99 
 
35 3 I 
1 
 
1204 9 7 
 
37 7.2 514 94 
 
8 1 714 15 
 
Table 3 in cludes the r esults obtained in 1916 with three different dust mixtures . The composition of these mixhues was as follows: 
Formula l. 9570 sulphur, 570 lea d arsenate. 
Formula 2. 60<J su lphur, 570 lead arsenate, 350/0 hydrated lime. 
Formula 3. 45% su lphur, 5 ]10 lead arsenate, 50'10 hydrated lime. 
These formula s are referred to by their r espective numbers in Table 3 under the h eading Treatm ent. 
11 
 
 In 1916 a n ew an d hitherto untried me t ho d of dustin g was adopted . Th e s p r ay wa g on wa s driven without stop ping and th e t r ees were r a p idly dusted in passing. The r esults of this m ethod prov e it to be th e ri ght on e. There wa s littl e or n o defolia t ion or fruit s plitting fol lowing three treatments , a nd a hi gh percen tag e of pea ch sea b and brown r ot con t r ol wa s r ealized. The color ing and ge ne r a l ma rketing- qu al ity of th e pea ches were good, and t he y brought among th e fa n ciest prices secu re d by uny of th e p;rowers of that sec t ion. 
Cu rc ulio cont rol in on e p lat was not as good a s it should have been. This pla t (Pla t 2) immediately adjo in ed t he untr ea ted che ck plat. The chec k plat, in t urn, lav al ong sid e of a bodv of wood in which curc ulios ha d hi bern ated in la r ge numbers. .1:\ part of P lat 2 a lso t ou ched the se wood s, and th e curc u li o infestation in bot h plats wa s high - in th e che ck amo unting to 88 pe r cent . In additio n to th e influ en ce of t he woods upon the d eg r ee of infest a t ion , th e old orchard in which t he spraying wa s done had r eceived but littl e cultiva tion and spraying for two year s previous. Th ere was an ab undance of ground lit t er and weecls throughout and just outsid e th e orchard, affo rding p lentiful prot ection to hib ernating cnrculio beetl es. Taking into cons ide r a t ion the fa ct t ha t this wa s an old , n egl ect ed orc h a r d, in close proximity to wooded land, with large numbers of OYer-wint ering cur culio within and just with ou t, th e fai lure of th e du st to con trol cureulio in festation better is expla ine d . 
Scab infections were of in signifi cant im p or tan ce. None of the peaches classifi ed a s scabbed was r ej ected wh en grading the f rui t for packing. Most of the scab infected p ea ches hare less than half a dozen small sp ots . 
COST . 
No depen da ble fig u r es bea ring on the relative cost of dusting , as against spraying, arc a t h an d at th is t im e. As st a te d, a g r eat deal more mat erial was used tha n was n ecessa r y , not to say desi r a ble, a nd, as t hese fig ures a re at pres ent th e on ly ava ilable on es, n o acc ur a t e basis of comparison is possible. The init ial cost of dust mater ia l i s greater than that of th e standar d liquid summer s p r a y mixtures . On the other hand, th e sa ving in time, labor and teams p robably wou ld mo r e than off set thi s differ en ce. I n th e continuation of th e expe r i- 
12 
 
 ment s, as at present proposed, the test s will he conduct ed on a larger scale with improved, mate ria l-conse rving equipment, an d fro m this work r eliable est imates of th e actua 1 and r elative cost of du sting will he secure d. 
Th e initia l outlay f or du sting equipment is less than fo r a good power p ump outfit. Th e latt er av erages abo ut thr ee hundred do lla r s. Du sting out fits, with engine att aclied, can be had fo r pr ices var ying from $150.00 to $225.00. 
DRY VERSUS LIQUID SP RAYI XG. 
Th ere is a tr emend ous ad vantage in dust ing as oppo sed t o sp raying, in actu al field oper ations . Am ong the se ad vantug cs ma y be menti oned: total depend ence of water su pply ; lightness of draught, en abling operati ons on wet fields; rapidity; ease and comf or t. It would also ap pear th at th er e is a mat er ially smalle r cost attached to it. T hese f act ors, added to fr uit in suran ce against destructive in sects and diseases, encour age the hop e and belief that th e du st method , with furth er experimentation , will prove so economica l and su ccessful as to render it worthy of ad option by frui t grO\' er s. 
Wi th du sting, a s with spraying, ther e is a co-or dinate r elationship betw een gener al or char d pra cti ces and losses sus t ained by insects and dis ea ses attacking fruit and folia ge. In othe r words, th e better cultivated , fe r tilized and winter sprayed an orchar d, th e better -an:.l bigger- the cro p, and the smalle r the nor mal liabili ty t o cr op losses by di seases or in sects. 
SU?\LM.A HY. 
At th e pr esent ti me the following obje cts have been pro ven a tt a inable with du st mixt ures : 
1. Alm ost perfect cont ro l of pe ach sca b, brown r ot . and cur culio. 
oj Good coloring of fruit. 
:L Th or ough and uni form distribution of mat eria l. 
-:1-. Saying of mor e than half th e t ime usuall y r equire d in s pr aying. 
;"). S aying" of la bor and t eams.. 
1~l 
 
 6. Saving- in initial cost of equipment. 7. Independ ence of water. 8. Little deterioration of du sting- mechani sm and none of material. Th e single dem erit of th e method may be stated as a t end ency of th e du st to burn leav es, defoliate trees and cr ack or check th e flesh of th e fruit when applied too heavil y. Thi s is mor e ma rked when a pp lica tion of material is closely fo llowed by rain. By th e use of improved ma chin ery, better methods of application, accurate r eg-ulation of output, and modification of formulas, th e reduction of thi s type of! injury to negli gibl e quan- . tities, or its complete eliminat ion, seems very probable. 
.A CK XO, VLE DGl\lENTS. 
Th e Department wish es to acknowl edge it s ind ebt ed ness to Mr. F. H. P ough, of th e Union Sulphur Co., of New York, for hi s interest and valuable colla bor ation in th e dusting- experiments, and for the donation of a11 du st material and du sting ma chin ery. Th e work ha s been g reat ly facilita ted throughout by ::\11'. Poug-h's suggestions and mate rial assist ance. 
Th anks are al so r eturned to Messrs. A. B. Veeder and Son and J . E. T hursby, r espectively, of Cornelia, fo r the allotment of plats for expe riment al spraying- and for th eir aid in othe r and important ways. 
14 
 
 LIST OF AVAILABLE PUBLICATIONS GEORGIA STATE BOARD OF ENTOMOLOGY. 
 
Bull. No. 13. Some Common Insects Injuriou s t o the A p ple. 
 
B ull. No . 26. P ea ch L eaf Cur l, Yellows, Ro sette and Little P ea ch. 
 
Bull. No . 34. , Yi]t Di sea se of Cott on in Geo rgia a nd its Con t r ol. 
 
Bull. No. 37. Cr op P est L aw of Geo rgia, Oth er States and Can ada . 
 
Bull. No. 40. Cot ton Wilt in Geor gia. 
 
Bull. No. 41. Som e of the More I m portant T ruck Cr op P ests in Georgia . 
 
B ull. No. 42. An n ual R epo r t of th e State E ntomologist f or 1914. 
 
Bull. No. 43. Th e P r incipal Para sites of t he P ea ch . Bull. No. 44. The Mex ican Cotton Bo ll , Yeeyil. 
 
B ull. No. 45. B ull. No . 46. 
 
An nua l R ep ort of th e State E ntomo logist 
fo r 1915. 
,T Cott on ar ie ty T ests fo r Bo ll W eevil and 
W ilt Conditions in Geo rgia. 
 
Cir cular No . G. Th e Use of So luble Oils Against San J ose S ca le. 
 
Circ ula r No . 7. T he H essian F ly in Georgia . Circ u la r No . S. Exp eriments fo r Con t r ol of San J ose 
Sc ale, 1907-1908. Cir cula r N o. 9. The B ro wn -Tail Moth. 
 
Circula r N o. 11. Wilt Disea se of Cotton a nd its Control with Suggestions on Seed Se . Iect ion . 
 
Cir cula r No . 19. B oll , Veevil Quaran tine R egul ations. 
 
15 
 
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