Balsam twig aphid
Mindarus abietinus
15 host plants
Last updated
On true firs (grand fir, silver fir, white fir) and balsam fir you will see honeydew-covered twigs with small glossy black aphids clustered at twig terminals in late summer and fall. Infested foliage shows sticky residue and sooty mold coating. Look for the aphids concentrating on new growth during August through October.
Prune and remove infested twig terminals before aphids produce overwintering eggs. Horticultural oil applied in March or April targets overwintering eggs on bark. If populations persist, spray insecticidal soap in late August when new generations appear. Preserve natural predators by avoiding broad-spectrum insecticides. Damage is typically cosmetic.
Quick Reference
All these aphids are light green in color. Spirea aphid is very difficult to separate from apple aphid without high magnification, whereas apple grain aphid can be distinguished by a yellowish green stripe down the middle of the back. Apple grain aphids infest pear only in the early part of the season, while apple aphid is present all summer. Aphids suck plant sap and live in colonies on new shoots. Populations are damaging only sporadically. Damage appears as rolled leaves, stunted terminal...
Cultural Controls
- Provide proper plant culture.
- Healthy plants can tolerate more insect damage.
- Avoid overfertilization.
- High levels of nitrogen in the foliage encourages aphid reproduction.
- Switch to a slow-release or low-nitrogen formula if necessary.
- Hose infested trees with a strong stream of water to wash off insects.