The sexual form begins with male and female eggs laid on the underside of young grape leaves. The male and female at this stage lack a digestive system, and once hatched, they mate and then die. Before the female dies, she lays one winter egg in the bark of the vine's trunk. This egg develops into the leaf form. This nymph, the fundatrix (stem mother), climbs onto a leaf and lays eggs parthenogenetically in a leaf gall that she creates by injecting saliva into the leaf. The nymphs that hatch from these eggs may move to other leaves, or move to the roots where they begin new infections in the root form. In this form they perforate the root to find nourishment, infecting the root with a poisonous secretion that stops it from healing. This poison eventually kills the vine. This nymph reproduces by laying eggs for up to seven more generations (which also can reproduce parthenogenetically) each summer. These offspring spread to other roots of the vine, or to the roots of other vines through cracks in the soil. The generation of nymphs that hatch in the autumn hibernate in the roots and emerge next spring when the sap begins to rise. In humid areas, the nymphs develop into the winged form, else they perform the same role without wings. These nymphs start the cycle again by either staying on the vine to lay male and female eggs on the bottom side of young grape leaves, or flying to an uninfected vine to do the same.