Woolly Apple Aphid

Hosts

Apple

Biology

Overwinter as nymphs primarily on the roots, but sometimes in cracks and crevices in the tree canopy.  White, cottony colonies are visible by mid to late June.  Their waxy covering makes them difficult to control.

Symptoms/Damage

Galls at feeding sites (twigs and roots); heavy feeding can reduce tree vigor; sticky colonies are messy during harvest.

Monitoring

Start monitoring for colonies in mid-June by checking root suckers and edges of pruning cuts and wounds.

Treatment Threshold

No threshold determined.

Degree Day Model

None

Management Considerations

If colonies are present, an insecticide treatment can be applied in early to mid-July.  If using spirotetramat (Ultor), apply at petal fall to allow time for translocation of the chemical within the tree.