Pest profile

Balsam Twig Aphid

Mindarus abietinus · Hemiptera: Aphididae[3]

Balsam twig aphids are tiny, waxy aphids that feed on buds and new needles of firs and some spruces in early spring, twisting and curling the needles and coating them with sticky honeydew and sooty mold.[1][2]

Balsam twig aphids covered in white waxy filaments among fir needles
Balsam twig aphids covered in white waxy filaments among fir needles. Photo: Dr. Alan Inman, public domain (CC0), via iNaturalist

How to identify it

  • Aphids are tiny (winged adults about 1/16 to 1/8 inch) and pale or blue-gray, covered with white waxy powder and filaments.[1][2]
  • Damaged new needles are twisted and curled, often sticky with honeydew.[1][2]
  • Overwintering eggs are dark and covered with small white waxy rods.[1][2]

Where it lives

NC State covers it on Fraser fir in North Carolina, and UMass on landscape firs and spruces in New England.[1][2]

Biology and life cycle

Overwintering eggs hatch in April and May into wingless stem mothers that give birth to 20 to 40 young without mating.[1][2]

Their offspring feed on buds and tender needles, so most damage happens early in the season.[1][2]

A winged generation appears from mid June to mid July, mates and lays the eggs that overwinter in bark cracks.[1][2]

Damage and signs

  • Preferred hosts are firs (alpine, balsam, Fraser, grand, Siberian and white); it can also develop on white and Colorado spruce and juniper.[1][2]
  • Heavy infestations reduce the value of Christmas trees and can stunt small trees; damage is often noticed only after the aphids are gone.[1][2]

Health risk

None to people or pets.[1][2]

Control

Biological control

As the weather warms, lady beetles, syrphid fly maggots, lacewing larvae and other predators help limit populations.[1]

Pesticides

Control is difficult because damage happens in early spring; insecticidal soaps and other landscape insecticides work only if applied early enough.[1]

Common questions

Why are the new needles on my fir twisted and sticky?
Balsam twig aphids feeding on new growth in early spring twist needles and leave honeydew.[1][2]
When do balsam twig aphids do damage?
In early spring, when stem mothers' young feed on buds and tender needles.[1][2]
Is it too late to spray once I see the damage?
Often, yes; by the time damage is noticed the aphids are usually gone.[2]

Sources

  1. NC State Extension, “Balsam Twig Aphid (PDIC Factsheet).” content.ces.ncsu.edu/balsam-twig-aphid (accessed 2026-10-15)
  2. UMass Extension Landscape, Nursery and Urban Forestry Program (Landscape Insect & Mite Guide), “Mindarus abietinus (Balsam Twig Aphid).” www.umass.edu/agriculture-food-environment/landscape/publications-resources/insect-mite-guide/mindarus-abietinus (accessed 2026-10-15)
  3. iNaturalist, “Mindarus abietinus taxon page (order and family).” www.inaturalist.org/taxa/454525 (accessed 2026-10-06)

Updated 2026-10-15. Built from sourced records. Spot an error? Tell us.