The role of extension

vitifoliae (Fitch) is becoming a more important pest of grapes as growers in Arkansas and in other north central states in the United States plant more French-American hybrid cultivars. Biology. Grape phylloxera, Daktulosphaira vitifoliae (Fitch), is a key pest of grape throughout the world. This pest has two forms that either attack the root (radicicola) or the foliage (gallicola). In humid climates like the Ozarks, grape phyl-loxera over winter either as immature grape phylloxera feeding on roots or as eggs laid on the trunk in the fall. During spring and summer, the root form produces several genera-tions that feed on the roots (Fig. 1) causing root tips to swell into nodosities (Fig. 2 and 3). In August, winged forms emerge from the soil and produce eggs. These eggs hatch and mature in September and early October into males or females that mate, and the female lays one egg that over winters on the trunk. In early April, eggs on the trunk hatch into first-generation yellow crawlers. These crawlers move to grape shoots to feed on the first to third expanding terminal leaves of the season. These leaves form a gall around each crawler (Fig. 4, inside). The first generation crawlers usually form less than five galls per leaf (Fig. 4). During April and early May, each crawler matures into a fundatrix or stem mother (center of Fig. 5, inside). Each stem mother produces a second generation of 100 to 300 oblong