Dasineura aceris

Dasineura aceris

Recognizable damage appeared on the new leaves while they were still curled. Affected leaves turned upwards and developed shallow pouch-like distortions on the leaf blades near the veins. About 20% of the infested leaves continued to grow and enlarge but often became distorted and tattered when growth tensions caused ruptures. When the occurrence was discovered in early July, the size of many of the larvae suggested that first oviposition must have taken place several weeks previously. Although oviposition was not observed, a cluster of unhatched but apparently healthy eggs was located on the upper surface of a partly folded leaf on July 25. The masses of white or pale cream larvae were found throughout the summer, often mixed instar groups of 20 or more in tightly curled leaves. As the leaves became distorted by the formation of the pouches, the larvae could be found in the crevices between the swellings and the larger veins. Late instar larvae were covered with a dense webbing under which pupation took place (Fig. 1). 

From the rather preliminary information obtained, Dasineura aceris, in the Sudbury area, emerges in the spring and infests the new leaves of silver maple as they begin to uncurl. Throughout the summer the various stages overlap until the leaves are too well developed for further oviposition. 

DASINEURA ACERIS (SHIMER) MIDGE ON SILVER MAPLE (DIPTERA: CEEIDOMYIDAE)