Feeding of Japanese Beetles on Phylloxera Galls

When the pecan leaf Phylloxera, Phylloxera notabilis Pergande, feeds on new spring hickory or pecan growth, a 3- to 16-mm-diam gall forms on leaves (Whitehead and Eastep 1937). The Phylloxeran (stem mother) matures within the gall and lays eggs that hatch in ca. 2 days. When the galls split in ca. 4–5 weeks the offspring escape. This type of attack causes the leaves to become malformed and weakened, and the hickory or pecan growth may defoliate prematurely.