Grape phylloxera has a very complex life cycle. They overwinter either as a winter egg under the bark of older canes or trunks or as nymphs on grapevine roots. The winter egg gives rise to the stem mother, or fundatrix. The fundatrix moves to a nearby shoot and begins feeding. Feeding causes a gall formation, and the female becomes enclosed within a small, spherical gall on the underside of the leaf. This female is capable of producing several hundred eggs. Crawlers emerge and move out of galls to nearby shoot tips where they begin feeding and thereby initiate formation of new galls. There are three to five generations of foliar phylloxera per season. Throughout the summer, a certain number of the foliar crawlers move to the soil surface and eventually reach the grapevine. Feeding by phylloxera on grapevine roots results in two types of galls. Nodosities are galls formed on small, apical rootlets. Feeding on the apical rootlets are generally thought to result in little damage to the vine. Tuberosities are galls formed on larger, older portions of the root which, if abundant, can cause severe damage, which may eventually lead to the death of the vine.

From July through October, some root-infesting phylloxera develop wing buds and eventually become fully winged adults. These adults emerge from the soil and lay two types of eggs. One large egg and one small egg. The larger egg will result in a female and the smaller egg will result in a male. These two mate and the female deposits a single overwintering egg under the bark of older canes or trunks, and the cycle starts over again.

Figure 1. Life cycle of grape phylloxera, Daktulosphaira vitifoliae (Fitch), (after Williams, 1938). (A) Winter egg, (B) foliar form (Gallicola), (C) root form (radicola), (D) winged adult, (E) sexual stage.