All oak species are susceptible. The blisters appear as depressions when the lower leaf surface is observed. Eventually the blisters may appear as a bright yellow-green color, and as the season progresses individual blisters turn brown. Blisters may coalesce on heavily infected leaves, such as those recently submitted to the lab, and symptoms may mimic severe anthacnose infections as well as noninfectious leaf scorch. It is also possible that all three of the aforementioned problems might occur on the sampe sample.
Heavy infection can result in defoliation.
Chemical control is not feasible on large trees. The descriptions are incredibly similar to that which was recently described in the Buckeye Yard and Garden Line as oak shothole leaf minor. Following is the information from their newsletter dated June 3, 1999. The female fly uses her ovipositor to puncture the leaf as it expands in May and she feeds on the sap oozing from the hole. Occasionally, the female will deposit a single egg into the feeding hole and the resulting larva produces a small, circular leaf mine.