Although several species of aphids attack pecans, the black pecan aphid is the most serious pest. The feeding of the aphids causes the discoloration of the leaves (as shown in the photo) and may cause them to drop prematurely. Loss of leaves can seriously affect the tree's food supply and filling of the nuts. In addition, the following year's crop will probably be reduced.
The black pecan aphid overwinters in the egg stage in crevices in the bark of pecan trees. In the early spring the eggs hatch into wingless aphids which feed on the opening buds. The aphids are light green at first, but as they feed they become almost black. When fully grown, the first generation gives birth to living young, some of which are winged forms. Up to 15 generations may occur in a single season. As cold weather approaches, eggs are laid for overwintering.
