Hop vine borer
- Adult: Tan or brown moth.
- Larvae: Caterpillar up to 2" long that is white with violet bands and a reddish-brown head.
- Eggs: Laid on grass stems in or near the corn field.
Timing of damage: VE to V3
Type of damage: Stem feeding: larvae tunnel up from underneath and hollow out the base of the stalk. Plants exhibit wilting, stunted growth or yellowing and can die.
Scouting: Dig up damaged corn seedlings along with a 3" to 4" cube of soil. Check the stalk for entry holes just below the surface, then split the stalk and sift through the soil for larvae.
Economic threshold: None established; insecticides are ineffective once the larvae has
burrowed into the plant. Crop rotation and elimination of grasses that serve as egg-laying sites are the best way to prevent this pest.