Three types of phylloxera (Phylloxera devastratrix) are pecan pests, but only pecan phylloxera causes economic damage in certain years.

The pecan leaf phylloxera and southern pecan leaf phylloxera feed primarily on the foliage, while the pecan phylloxera attacks the foliage, shoots and fruits and is therefore the most harmful. The pecan phylloxera is a small, aphid-like insect that is rarely seen, but the galls it produces are showy and easy to spot. Severe infestation leads to malformed, weakened shoots that eventually die off. Such an infestation can destroy entire limbs.

The pecan phylloxera overwinters as eggs that are in the corpse of an adult woman, who are in sheltered places on the branches of pecan trees. Soon after the buds break, the eggs hatch and the young insects migrate to opening buds or leaf tissue to feed on expanding new growth.

The individuals that hatch from the hibernating eggs are known as tribe mothers. Feeding by the ancestral mother stimulates the development of galls, which enclose the ancestral mother in a few days. The ancestral mother matures in the gall, lays her eggs and dies. Eggs laid by the ancestral mother hatch in the bile, and these nymphs feed in the bile until they mature.

In early July, the galls split and the mature nymphs emerge as winged, asexual adults. These adults migrate to other trees or other parts of the same tree and lay eggs of two sizes. The smaller eggs hatch into males and the larger eggs hatch into females. Male and female sexes do not feed; Their sole purpose is to mate and produce the hibernating egg. After mating, female sexes seek sheltered spots on a tree where they die with a fertilized egg that is sheltered for the winter.

description

The adults and nymphs are small, an inch long, soft, and cream-colored. They resemble aphids without a cornea (the protruding tubes at the dorsal end of the aphids). You will need a hand lens to observe and identify them.

Scouting and control

Because the galls are easy to see, the pecan phylloxera infestation often appears worse than it is. Once the galls appear, it’s too late to control pecan phylloxera for the season. In most cases, however, there is no need to raise major concerns as they typically do not do enough damage to pecan trees to warrant insecticide use.

If you’re looking to apply an insecticide, try Bayer Advanced Fruit, Citrus and Vegetable Insect Control for systemic control that doesn’t require spray application. Only the trees infested in the previous year need to be treated, not the entire orchard. Certain native trees and grafted varieties in an orchard are more infested than other trees.

Sherri Sanders is a County Extension Agent – Agriculture with the White County Cooperative Extension Service. You can reach them on (501) 268-5394 or by email at [email protected]