Woolly Apple Aphid
Biology: Overwinter as nymphs primarily on the roots, but sometimes in cracks and crevices in the tree canopy. Cottony colonies are visible by mid to late June. Their waxy coverings make them difficult to control.
Symptoms: 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.