Phylloxera caryaeren

Riley, 1874

pecan phylloxera, pecan stem phylloxera

Phylloxera caryaeren is a small, soft-bodied, gall-forming insect closely related to aphids that attacks pecan trees (Carya illinoinensis). It is considered the most damaging phylloxera on pecans because it attacks shoots and developing nuts, unlike the pecan leaf phylloxera which only affects foliage. Heavy can reduce current-year yield, impair tree vitality, and reduce production in subsequent years. The insect is sedentary and cannot fly long distances, so infestations spread slowly from tree to tree.

Phylloxera caryaeren by no rights reserved, uploaded by Ken Kneidel. Used under a CC0 license.Phylloxera caryaeren by no rights reserved, uploaded by Ken Kneidel. Used under a CC0 license.Phylloxera caryaeren 205300706 by Ken Kneidel. Used under a CC0 license.

Pronunciation

How to pronounce Phylloxera caryaeren: //fɪˈlɒksərə kɛəˈraɪəˌrɛn//

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 or similar ) by gall location: P. caryaeren forms galls on shoots and nuts, while leaf phylloxera forms galls only on leaf tissue. Galls range from 1/10 to 1 inch in diameter and appear on new growth in spring. Infested shoots and nuts develop conspicuous swollen growths. Galls eventually crack open to release winged . Survey orchards in May to mark infested trees for treatment the following spring.

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Appearance

Tiny, soft-bodied insect resembling an . Nymphs are minute and pale. are winged forms that emerge from galls. The is distinguished by the galls it produces on pecan shoots and nuts rather than by direct visual characteristics of the insect itself.

Habitat

Pecan orchards and native pecan groves. Requires pecan trees (Carya illinoinensis) as . Favors conditions where pecan bud break occurs in spring, with new growth providing feeding sites for emerging nymphs.

Distribution

Pecan-growing regions of Texas and the southeastern United States. Distribution corresponds to the range of commercial pecan production. Native trees and improved varieties throughout this range show varying susceptibility.

Seasonality

hatch during pecan bud break in spring. Nymphs feed on new growth and induce gall formation when shoots are 1-2 inches long. Winged emerge from galls in late spring to early summer. Unlike leaf phylloxera, this does not produce second or third within the same season. Females hide in bark crevices and die, with eggs protected inside their bodies through winter.

Diet

Feeds on pecan tree tissues by inserting needle-like mouthparts into new growth. Nymphs stimulate abnormal plant development that forms galls, which provide both food source and shelter. Feeding occurs inside galls on shoot and nut tissues.

Host Associations

  • Carya illinoinensis - primary Pecan; attacks shoots and nuts

Life Cycle

Overwinters as protected inside dead female bodies in bark crevices. Eggs hatch in spring during bud break. Nymphs feed on new growth and secrete substances inducing gall formation. Development completes inside galls. Winged emerge when galls crack open. Adults deposit eggs; females hide in protected bark locations, die, and eggs remain inside their bodies through winter. Single per year; no second generation produced.

Behavior

Nymphs are sedentary, remaining at feeding site and inducing gall formation. Cannot fly long distances; spread slowly from tree to tree. emerge from galls and move to deposit . Females seek protected locations on bark for egg deposition.

Ecological Role

Pest of pecan production. Gall formation disrupts normal shoot and nut development. Heavy reduce tree photosynthetic capacity and nutrient allocation to nuts. No documented beneficial ecological role.

Human Relevance

Significant economic pest of commercial pecan production in Texas and the Southeast. Most damaging phylloxera on pecans due to direct attack on reproductive structures (nuts) and vegetative shoots. Control relies on preventive applications timed after bud break when new growth is 1-2 inches long, before nymphs become enclosed in protective galls. Spot treatment of infested trees is often sufficient due to limited ability. Variety selection for resistance is recommended as part of .

Similar Taxa

More Details

Management timing

applications must occur after hatch in spring but before nymphs induce galls and become enclosed. Treat when new growth is 1-2 inches long, typically shortly after bud break. Once galls form, insects are protected from contact insecticides.

Cultivar susceptibility

Native pecan trees and improved varieties vary in susceptibility to phylloxera attack. This variation can be exploited through cultivar selection in orchard establishment.

Monitoring recommendations

Survey orchards in May to identify and mark trees with galls. This allows targeted treatment of only infested trees the following spring, reducing unnecessary use.

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Sources and further reading