NC State Extension Publications

Description and Biology

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The balsam twig aphid, Mindarus abietinus, has a complex life history with three distinct forms occurring during a single generation. Winged balsam twig aphids are 1/16 to almost 1/8 inch long. In the spring overwintering eggs hatch. After three molts, nymphs develop into wingless adults called stem mothers that give birth to living young. The stem mothers are plump, covered with a snowy powder and often obscurred by waxy filaments protruding from their abdomens. Whereas many aphids have conspicuous cornicles, those of the balsam twig aphid are much reduced. Offspring gather in a colony around the greenish or blue-gray parent and feed on old needles and buds. Offspring also produce a white waxy covering over ther bodies. Nymphs are very small, pale yellowish-green and wingless. Plump nymphs develop into wingless females (called fundatrices) that give birth to more nymphs. From mid June to mid July, slender nymphs are born that develop into winged female and male adults called sexuales. These winged aphids mate, lay eggs, and disappear. The rest of the year is spent as eggs in crevices of the bark or sometimes on needles. Eggs are black and covered with small, white rods of wax.

balsam twig aphid

Winged balsam twig aphids are small and covered with a fluffy secretion.

balsam twig aphids

Early in the growing season balsam twig aphids are wingless.

Balsam twig aphids spend most of the year as eggs

Balsam twig aphids spend most of the year as eggs.

Host Plants

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This insect has been reported on alpine fir, balsam fir, Fraser fir, grand fir, Siberian fir, and white fir. When populations are high on firs, some aphids fall onto other conifers and can complete their development on white spruce and juniper. Balsam twig aphids excrete copious amounts of honeydew in which can develop black sooty mold fungi. Aphid feeding may also cause twists and curls in the needles as well as roughened bark. Heavy infestations can reduce the value of Christmas trees and even cause stunt small trees.

Balsam twig aphids cause twisted needles on Fraser fir.

Balsam twig aphids cause twisted needles on Fraser fir.

Balsam twig aphids distort the needles of spruces as well as fir

Balsam twig aphids distort the needles of spruces as well as firs.

Residential Recommendations

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Control of balsam twig aphids is difficult because damage occurs in early spring when weather is unpredictable. Insecticidal soaps and other insecticides labeled for landscape use should be effective in preventing noticeable damage if applied early enough. As the weather warms up, lady beetles, syrphid maggots, aphid lions and other predators help limit balsam twig aphid populations.

Other Resources

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

This publication has not been peer reviewed.


Professor Emeritus
Entomology & Plant Pathology

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Publication date: March 13, 2019
Revised: Dec. 20, 2023

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