Gall producing insects

Gall Producing Insects
Galls are abnormal vegetative growths on trees that result from the feeding and egg laying activities of various insects and mites. Chemical secretions deposited by adults while laying eggs combined with saliva from feeding larvae cause the plant to react abnormally. The most common gall producers on trees are aphids, beetles, jumping plant lice, midges, mites and wasps. Each species causes a characteristic swelling of plant tissue on the stem, twig, leaf or petiole. Galls are more readily identified than are gall producers. Galls and their producers are commonly identified by noting the gall's shape and specific location.
Generally, galls are not life threatening to trees. Oftentimes the most drastic effects are premature leaf fall and dieback of several smaller branches. On small trees, galls should be pruned and destroyed. Leaf and twig litter around the tree's base should be raked and discarded. A few of the common gall species are shown in figures below.

Cynipid Oak Gall

Leaf Gall on Black Cherry

Wool Sower Gall on White Oak

Maple Eye Spot Gall

Horned Oak Gall

Pecan Leaf Phylloxera Gall

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