NC State Extension Publications

Description and Biology

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The beech blight aphid, Grylloprociphilus imbricator, is a small (early nymphs) to medium sized aphid (older nymphs and adults) that is bluish gray. The rear half of the abdomen may be obscured with a dense, white, fluffy secretion interspersed with long, slender, white filaments. Sometimes on beech these aphids increase to enormous numbers to the point that the mass of aphids is practically hidden by the long, white, fluffy filaments and the colony may extend up to five feet along a branch. Beech blight aphids spend the winter on the roots of bald cypress where they are little noticed. On beech, the colonies persist as white, fluffy masses from April through November in North Carolina. During that time, winged beech blight aphids leave the colony to fly to bald cypress. During the winter, aphids from the roots of bald cypress fly to beech where they lay eggs for the next spring generation. Beech blight aphids become a real nuisance because of the honeydew they excrete, the sooty molds that grow in the honeydew, and the appearance of the aphids themselves. The sooty mold associated with this aphid is Scorias spongiosa that may form a black, thick, spongy mass. The beech blight aphid sometimes becomes amazingly abundant even on forest trees. Aphid populations are sometimes devastated by Cephalosporium lecanii, a fungus that infects aphids as a sort of super athlete's foot disease. Beech blight aphids are also known as boogie-woogie aphids because when a colony is disturbed, the nymphs lift their abdomens high in the air and thrash in unison as an apparent warning to predators. Beech blight aphids are threatened by parasites and predators. However, nymphs of these amazing aphids can use their mouthparts to “sting” predators, effectively protecting the colony. Indeed, beech blight aphids may even sting an unwary observer who allows them to come into skin contact! The aphids, their grunge and sooty molds may persist for some months.

Beech blight aphids

Beech blight aphids excrete honeydew that further disfigures its host, beech.

Beech blight aphids persist

Beech blight aphids persist on beech throughout the summer and fall.

beech blight aphids fly

During the summer and fall, beech blight aphids fly to infest the roots of bald cypress.

Host Plants

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The beech blight aphid cycles from bald cypress (and perhaps Cryptomeria) to American beech.

Residential Recommendations

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Pyrethroid insecticides, horticultural oil sprays (weather permitting), and insecticidal soaps should provide adequate suppression. Imidacloprid, a systemic insecticide, is generally very effective against aphid species but may take weeks to reach the aphid on twigs and branches overhead. These insecticides can be found at big box stores and garden centers.

References

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For assistance with a specific problem, contact your local Cooperative Extension Center

This Factsheet has not been peer reviewed.

Author

Professor Emeritus
Entomology and Plant Pathology

Publication date: Jan. 7, 2017
Revised: Oct. 9, 2019

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