Description of the Pest
Darkling beetle adults range from 0.12 to 0.25 inch (3–6 mm) long and are about half as wide. They are dirty black to rusty brown in color, but this may be obscured by dust or a thin layer of soil. Larvae are very similar to wireworms in appearance.
Damage
Beetle adults girdle or cut off seedlings at or below the soil surface, and are mostly active at night. After plants reach a height of 4 to 6 inches, darkling beetles are usually not a problem. Darkling beetles sometimes invade cotton from grain fields, weedy areas, or from adjacent alfalfa.
Management
Watch for darkling beetle injury by walking the field during the seedling stage. Pay special attention to field edges and any low or weedy areas. Currently there are no bait products registered for control of darkling beetles in cotton.