Pest description and crop damage The adult aphid is black, globular in shape and about 1/8 inch long. Black cherry aphid is the only black aphid on cherry. These aphids curl foliage, reduce terminal growth, and deposit honeydew on cherries which can be difficult to remove prior to commercial packing. Damage to young trees can be significant.
Biology and life history The aphids overwinter as eggs in crevices and twigs. The eggs hatch near budbreak, and the nymphs feed on unopened buds and the undersides of leaves. Nymphs inject a toxin into leaves, causing them to curl and protect the aphids as they feed. After two to three generations, winged forms are produced that migrate to summer hosts, which include weeds, ornamental plants, and vegetables, or plants of the mustard family. After several more generations, the winged forms migrate back in the fall to the fruit tree to mate and lay the overwintering eggs.
Pest monitoring Begin observing shoots before budbreak, as management is best undertaken early while the aphids are small and prior to leaf curl.
Aphids have many natural enemies, which include ladybeetles, syrphid fly larvae, and green lacewings. Avoid broad-spectrum insecticide applications that would disrupt these controls.
Home orchardists: Wash aphids from plants with a strong stream of water or by hand-wiping. Aphids are difficult to control once leaves begin to curl as insects are protected within the curled leaf from direct contact by water and chemicals. Aphid populations tend to be higher in plants that are fertilized liberally with nitrogen. Avoid excessive watering which, together with nitrogen applications, produces flushes of succulent growth.
Management-chemical control: HOME USE
Warning: Many pesticides are hazardous to bees. Look for bee precautionary statements on product labels and do not use these products during bloom or if bees are foraging in the orchard.
- pyrethrins-Some formulations are OMRI-listed for organic use.
Management-chemical control: COMMERCIAL USE
Warning: These materials are hazardous to bees. Do not use during bloom or if bees are foraging in the orchard.
Dormant-season and delayed-dormant sprays
- chlorpyrifos (Lorsban 75 WG) at 2 lb/a. REI 4 days. Do not exceed one application of chlorpyrifos as a dormant or delayed-dormant per season. Avoid contact with foliage in sweet cherries as premature leaf drop may result. Extremely toxic to fish and aquatic invertebrates; avoid spray drift and runoff to surface waters.
- diazinon (Diazinon 50W) at 1 lb/100 gal water (4 lb/a). REI 4 days. May be applied with a dormant oil spray (see labels for rates). Do not exceed one dormant application per year.
- dimethoate (Dimethoate 400 EC) at 1 quart/a. REI 10 days (14 days in areas where average annual rainfall is less than 25 inches). Do not exceed one pre-harvest application per season. Can cause leaf burning and fruit marking. Do not use on cherries to be exported to Japan.
Spring and summer sprays
- acetamiprid (Assail 70WP) at 1.1. to 2.3 oz/a. REI 12 hr. PHI 7 days.
- diazinon (Diazinon 50W) at 4 lb/a. REI 4 days. PHI 21 days. Do not exceed one in-season foliar application per year.
- esfenvalerate (Asana XL) at 4.8 to 14.5 fl oz/a. REI 12 hr. PHI 14 days. Asana may aggravate spider mite problems. Extremely toxic to fish and aquatic invertebrates; avoid spray drift and runoff to surface waters.
- imidacloprid (Provado 1.6F) at 4 to 8 fl oz/a. REI 12 hr. PHI 7 days. Do not use until pollination is complete and bees are no longer present in canopy or ground cover.
- malathion (Malathion 57EC)-Rates vary by product, check label. REI 12 hr. PHI 3 days. Malathion may be used in the evening after bee activity. Do not apply within 300 ft of aquatic habitat.
- spirotetramat (Movento) at 6 to 9 fl oz. REI 24 hr. PHI 7 days. Do not apply until after petal fall.
- thiamethoxam (Actara 25WDG) at 3 to 4 oz/a. REI 12 hr. PHI 14 days. Actara is extremely toxic to bees exposed to direct treatment or residues.