Aphids

Pest Description

• most less than 1/8 inch; over 500 aphid species in Utah
• range in color from green, yellow, purple, red to black
• teardrop to oval in shape with two “pipes” (cornicles) sticking out the rear end
• some aphids excrete a white, cottony substance
• may or may not have wings

Host Plants, Diet & Damage

• some are host specific; some feed on multiple host plants
• feed on plant sap using straw-like mouthparts
• can feed on roots, trunk, stems or leaves
• can cause twisting, cupping, leaf rolling, galls and unsightly cottony masses
• do not typically cause major tree/plant health issues
• exude honeydew onto plants, homes and cars
• sooty mold growing on honeydew can be unsightly
• mass fall migrations can sometimes cause alarm
• some transmit plant diseases

Biology, Life Cycle & Damaging Life Stage

• life cycles are variable depending on aphid species
• overwinter as eggs outdoors
• mating may occur; females can give birth to living young
• wings may form during migrations between hosts or when populations become too high
• nymphs and adults are the damaging life stages

IPM Recommendations

• Little negative effect on tree health; tolerate pest.
• Wash off aphids with a strong stream of water.
• Apply horticultural oils to overwintering eggs in spring.
• Apply insecticidal soap to nymphs and adults.
• Apply a systemic insecticide (neonicitinoid) in the spring.
• Apply a cover spray (pyrethroids) when aphids are present.