Black Bean Aphid

Order: Hemiptera
Family: Aphididae
Species: Aphis fabae

Pests as nymphs and adults

Appearance

• 1/8 inch long
• Globular soft bodies (tear-drop, pear-shaped)
• Light-colored legs with darker “knees” and “ankles”
• Twin “jet-pipe” cornicles (backward pointing abdominal tubes)
• Olive-green to black bodies
• May or may not have wings
• Piercing/sucking mouthparts

Damage

• Direct damage: suck sap from leaves
• Indirect damage: transmission of BWY virus

Symptoms

• Leaf curling & distortion, especially young leaves at the center of the crown
• Dense colonies on the underside of leaves and white cast skins from prior generations
• Leaf yellowing and wilting (first along the edges)
• Honeydew and black sooty mold

Biology

Winter

Overwinter as eggs on Euonymus (burning bush) and Viburnum (snowball bush)

Spring

2–3 generations on winter hosts as wingless, asexual females before producing winged asexual females

Summer

Colonizing flights to summer hosts (beans, corn, sugar beets, lamb's-quarters, pigweed) and have explosive, multiple generations (wingless, asexual females)

Fall

Winged asexual females and winged sexual males return to winter hosts and have 1 generation of sexual females to produce eggs

Control Strategy

• Minimize initial colonization and establishment
• Slow rate of increase once established

Control Measures

Biocontrol

• Conserve natural enemies (lady beetle larvae and adults, lacewing larvae and adults, hover fly, parasitic wasps) by learning to recognize them and managing foliar insecticides
• Supplement food and habitat for natural enemies with “insectary plants” (alfalfa, buckwheat, clover, mint, vetch)
• Mass release from commercial insectaries
  • Suppliers of Beneficial Organisms
  • Association of Natural Bio-Control Producers

Scouting

University of California

• Visually inspect individual plants each week
• Estimate the average % of leaf area with aphids

Colorado State University

• Visually inspect plants in 10-ft rows weekly
• Rate plants as infected or not infested based on the number of new leaves with aphids

Pesticides

Ecologically selective applications:

1. Spot spray aphid infested areas instead of the entire field
2. Use soil-applied systemic insecticides for aphids instead of foliar-applied contact insecticides
3. Use caterpillar stomach poisons instead of contact poisons
4. Check the Database of Pesticides Registered in Idaho (Kelly Database) for pesticides registered in Idaho