Twisting of the plant is typical of stink bug feeding injury.

June 13, 2008

A crop consultant reported finding stink bugs feeding on the base of seedling corn plants in Saunders County and sent these photos.

Stinkbug feeding.

We have been receiving more frequent reports the last few years of stink bug damage to corn. Stink bugs insert their needle-like mouthparts into the base of seedling corn plants to inject salivary enzymes into the plant. These enzymes help stink bugs feed on the plant tissue.

Depending on the plant stage attacked, injury symptoms may include death of the growing point, leaf distortion and twisting of the plant, or yellow streaks or holes in the leaves as they emerge from the whorl. Previous observations indicate that fields where the seed furrow was not fully closed due to planting during wet field conditions may favor injury by stink bugs by allowing access to the plant's growing point below ground.

We cannot identify the stink bug species based on these photos, but they are likely one of the Euchistus species, which include the brown stink bug and onespotted stink bug. These may overwinter in Nebraska and begin feeding in fields of alfalfa or small grains, and then migrate to corn as it emerges. Often injury appears first on the field border as the stink bugs move into the field. If damage is observed soon enough, it may be possible to only treat the field border. With time the stink bugs can move throughout the field.

There is no published research to establish an economic injury level for these insects, but some states suggest that black cutworm thresholds should be used.

Bob Wright
Extension Entomologist, Lincoln
Tom Hunt
Extension Entomologist
Haskell Ag Lab, Concord