Chinch bugs have historically been a problem in Kansas--in lawns, golf courses, turf farms, etc. But in agriculture, they are mainly a problem in sorghum. However, they can also affect corn and occasionally wheat. Since they are true bugs, chinch bugs may attack any grass where they insert their mouthparts into the plants and suck out the juice. This often has little to no effect on the plant unless there are large numbers of bugs and/or the plants are growing under less-than-ideal conditions so that they are already stressed. Chinch bug feeding simply adds to this stress.
Sampling for chinch bugs the week of July 4 indicated that 95% of the chinch bug population in north central Kansas were adults (Figure 1). Adults don't feed as much as nymphs but are more concerned with mating, oviposition, etc. This means the majority of feeding in crops (sorghum, corn, etc.) is still to come after the nymphs hatch (Figure 2).
Treating for chinch bugs needs to be accomplished using as much carrier (water) as practical to ensure the insecticide gets good coverage on the plants, including the base of the plants (sprays directed at the base of the plants will help). Nymphs produced now will most likely become adults in 3-4 weeks, then mate and start the process all over again for another generation, which will then move to fall-planted wheat, then on to overwintering sites. They overwinter in bunch grasses then move to wheat in the spring to deposit eggs and start all over again.
Figure 1. Adult chinch bugs. Photos by K-State Entomology.
Figure 2. Chinch bugs as nymphs. Photos by K-State Entomology.
Jeff Whitworth, Extension Entomologist