Phylloxera caryaegummosa

Riley, 1874

pecan phylloxera

Phylloxera caryaegummosa is a tiny, soft-bodied insect in the Phylloxeridae, closely related to aphids. It is a significant pest of pecan (Carya illinoinensis), causing galls to form on shoots and nuts. This is considered more damaging than pecan leaf phylloxera (Phylloxera notabilis), which affects only leaves. Heavy can reduce yield, impair tree vitality, and curtail subsequent production. The insect has a complex involving multiple and forms, with winter survival as protected within the bodies of dead females.

Pronunciation

How to pronounce Phylloxera caryaegummosa: /fɪˈlɒksərə ˌkɛərɪəˌɡʌˈmoʊsə/

These audio files are automatically generated. While they are not always 100% accurate, they are a good starting point.

Identification

Distinguished from pecan leaf phylloxera (Phylloxera notabilis) by its attack on shoots and nuts rather than leaves alone. Identified by the presence of galls on new shoot growth and developing nuts, ranging from 1/10 to 1 inch in diameter. Galls crack open in late spring to release winged . The does not produce second- galls within the same season, unlike leaf phylloxera.

Habitat

Found exclusively in pecan orchards and areas with native pecan trees. Requires new, rapidly expanding growth for gall formation. occur on new shoots during bud break in spring.

Distribution

Recorded from pecan-growing regions of the United States, particularly Texas and surrounding states. Native range corresponds to the natural distribution of pecan (Carya illinoinensis) in North America.

Seasonality

hatch during bud break in spring. Nymphs feed and induce gall formation on new growth when shoots are 1–2 inches long. Winged emerge from galls in late spring. eggs remain in bark crevices until the following spring. No second of galls is produced in the same season.

Diet

Feeds on phloem sap of pecan trees (Carya illinoinensis), specifically on new shoot growth and developing nuts. Nymphs feed within protective galls they induce on tissue.

Host Associations

Carya illinoinensis - primary pecan; attacks shoots and nuts

Life Cycle

Overwinters as retained within the bodies of dead females in bark crevices. Eggs hatch in spring during bud break. Nymphs crawl to new growth and feed, inducing gall formation through secreted substances that stimulate abnormal plant tissue development. Nymphs complete development inside galls, which range from 1/10 to 1 inch in diameter. Galls crack open in late spring, releasing winged . Unlike pecan leaf phylloxera, this does not produce additional galls; females hide in protected bark locations, die, and their eggs overwinter inside their bodies.

Behavior

Nymphs are sedentary, remaining within galls after induction. Winged emerge from cracked galls and disperse to bark crevices. Females do not deposit externally; eggs remain inside the mother's body for winter protection. spread slowly between trees because adults cannot fly long distances.

Ecological Role

Acts as a gall-forming herbivore that manipulates plant tissue for shelter and nutrition. Galls may provide temporary for other insects, such as hickory shuckworm larvae which have been observed feeding within phylloxera galls in spring. Serves as prey for including lacewings, lady beetles, and spiders in pecan .

Human Relevance

Economic pest of commercial pecan production. Heavy reduce nut yield and tree vitality. Management requires application timed after hatch but before gall formation protects nymphs. Treatment timing is critical: apply when new growth is 1–2 inches long. Only infested trees require treatment due to limited ability. Native and improved pecan varieties vary in susceptibility.

Similar Taxa

Phylloxera notabilisAlso called pecan leaf phylloxera; forms galls only on leaves, not shoots or nuts. Produces second and sometimes third of galls in one season, whereas P. caryaegummosa does not.
Phylloxera caryaecaulisHickory phylloxeran found on hickory (Carya); forms galls on leaf blades and petioles rather than shoots and nuts.

More Details

Management timing

applications must occur after bud break when new growth is 1–2 inches long, after hatch but before nymphs induce galls that would protect them from chemical exposure. Surveying orchards in May to mark gall-bearing trees allows targeted treatment the following spring.

Cultivar susceptibility

Native pecan trees and improved varieties show differential susceptibility to phylloxera , though specific cultivars are not detailed in available sources.