Vein Pocket Gall, Macrodiplosis quercusoruca

Hosts: Oak
Symptoms: Vein pocket galls are caused by the larval stage of small flies called gall midges (gnats), family Cecidomyiidae. The tiny maggots cause elongate, pocket-like swellings to occur along midribs and lateral veins on pin oak leaves.
Life Cycle: The infestation begins in early spring when the newly unfolding leaves begin to flatten out , which coincides with egg laying by the gall midge female. The tiny maggots move to the leaf veins where they begin to feed. Within a few days gall tissue forms about and covers the feeding larvae. Development is usually complete by mid-spring, when mature larvae emerge, drop to the ground, and remain there until the cycle repeats next spring. There is usually one generation per year.
Description: Adult gall midges are minute flies that rarely exceed 3mm in length. Mature larva are about 2mm long, whitish, and usually have a sclerotized plate on the ventral surface of the mesothorax.
Control: Please contact your local county extension office for current information.
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