Rosy Apple Aphid
Biology: Overwinter as eggs in protected areas on limbs and start hatching at half-inch green. Migrate to alternate weed hosts during summer.
Symptoms: Curled leaves; honeydew; saliva of rosy apple aphid is toxic to fruit cells, resulting in deformed fruit.
Monitoring: Look for shiny black eggs in early spring. Starting at open cluster stage, examine at least 10 trees, spending 3 minutes/tree, and look for colonies.
Treatment Threshold: Delayed dormant oil will usually take care of this aphid. Otherwise, an average of more than one colony per tree may result in fruit injury.
Degree Day Model: none
Management Considerations: Numerous beneficial insects including lady beetle adults and larvae, lacewing larvae, and syrphid fly larvae help suppress aphid populations.