NC State Extension Publications

Description and Biology

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The hickory peach gall midge, Cariomyia persicoides, causes small, fuzzy, more or less spherical galls on the lower side of hickory leaves. These galls appear much like some of the leaf galls of cynipid gall wasps and psyllid gall makers, but when the galls are opened, a maggot is found inside each gall. These maggots have a peculiar "breast bone" structure that is visible through the integument typical of cecidomyiid larvae. Gall midge maggots drop from the galls to pupate in the soil in a thin, silken cocoon. The following year, a new generation of tiny, mosquito-like gnats emerges from the soil to lay eggs on the developing buds of hickories in early spring. This causes a chemical response in the leaf resulting in gall formation. This gall is rarely abundant enough to cause injury to the tree but some people find them to be an aesthetic problem. It is not unusual for insect populations to fluctuate drastically from year to year and place to place. Next year the galls may not show up at all. On the other hand, they may be worse!

Hickory peach galls

Hickory peach galls are found on the undersides of hickory leaves.

Hickory peach galls are spherical

Hickory peach galls are spherical and hollow.

hickory peach gall maggots are more or less colorless

Unlike some other gall midge maggots that are orange or yellow, hickory peach gall maggots are more or less colorless.

Host Plants

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Hickory is the only host reported for the hickory peach gall midge.

Residential Recommendations

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By the time the galls are noticed, it is usually too late to apply an insecticide to kill the maggots inside the gall. If chemical control is desired for the next year, consider spraying the tree with some sort of contact/systemic pesticide such as acephate or imidacloprid just as the buds are breaking in early spring.

Other Resources

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For assistance with a specific problem, contact your local Cooperative Extension Center.

This Factsheet has not been peer reviewed.

Author

Professor Emeritus
Entomology & Plant Pathology

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Publication date: May 27, 2020
Revised: April 27, 2020

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