Corn root aphid
- Adult: Bluish-green or gray round, soft-bodied insect about the size of a pinhead. Subterranean and remain in the soil year-long. Secrete a sticky sugary substance called honeydew and feed on plant juices through the roots.
- Nymphs: Look like adults but smaller.
- Eggs: Females do not lay eggs but give birth to live young.
Timing of damage: VE to V12
Type of damage: Wilted, yellow or brown and/or stunted plants.
Scouting: Dig up wilted plants and inspect roots for aphids. Corn-field ants feed on the honeydew these aphids produce, so anthills will often be seen at the base of infected plants.
Economic threshold: No established threshold. In good conditions, plants will outgrow damage. Tillage can also help reduce aphid numbers.