PECAN PHYLLOXERA (PPX): Phylloxera devastatrix Pergande Order - Homoptera: Family - Phylloxeridae

DISTRIBUTION: Pecan phylloxera can be found in Alabama, Arkansas, Georgia, Louisiana, Mississippi, Oklahoma and Texas.

DESCRIPTION:Eggs (0.5 mm) are found inside the dead, mummified adults or in galls. Nymphs (Fig 1-grape phylloxera shown) resemble wingless adults and are usually found in galls (Fig 2). Adults (3-4 mm) are cream-colored and resemble aphids (Fig 1-grape phylloxera shown), but without cornicles. Adults may or may not have wings. If wings are present, they are held flat over the back and have few veins.

HOSTS: Pecan and hickory

DAMAGE: Large infestations can cause severe defoliation and stem breakage, leading to reduced crop production and misshapen trees.

INSPECTION TIPS: Inspection methods are similar to those utilized for aphids. Inspect foliage for leaf and stem galls (Fig 3 & 4) and malformed shoots & nutlets (Fig 5). Sweep branches with a sweep net for winged adults. Shake or beat branches over a white sheet or other light colored material for free roaming nymphs and adults.

LIFE CYCLE: Eggs overwinter inside the dead, mummified bodies of adult females in protected places on the host tree. They hatch during spring budbreak, and nymphs migrate to open buds or nearby leaflets to feed. These early nymphs are called “stem mothers.” Feeding stimulates growth of gall tissue around the stem mothers as they mature. Mature stem mothers lay unfertilized eggs and die within the galls. These eggs develop into winged asexual adults that abandon their galls to lay eggs on exposed surfaces nearby or on other trees. Eggs from the asexual adults develop into sexual males and females. As the weather cools in fall, mated females seek out sheltered places for overwintering on the host and die containing their fertilized eggs.

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