As the brown marmorated stink bug (BMSB) increases in numbers in Central and Western Kentucky, we will see it attacking various crops. Sweet corn is one crop that it can build to high numbers on, while also inflicting serious injury. Stink bugs are attracted to sweet corn as it moves into the milk stage of ear development. Sweet corn is also one of the crops that young BMSB will develop on. The nymphs and adults penetrate through the husk leaves of ears to feed on developing kernels with their piercing-sucking mouthparts. This results in shriveled and partially shriveled kernels that can turn brown. When numbers are high, BMSB have the ability to ruin a crop.
As with corn earworm, planting date is very important; sweet corn that matures in early July is likely to be harvest before BMSB populations are at their highest. However, sweet corn maturing in late July and August may be more likely to have issues with BMSB. Sweet corn maturing later in September may have less risk to BMSB.
In terms of insecticidal control, treat if substantial numbers are found on the husk leaves of ears. There are no preventive treatments and the Bt sweet corn hybrids have no resistance to stink bugs. If an insecticide is needed, one of the pyrethroids listed in Vegetable Production Guide for Commercial Growers (ID-36) should be used.
By Ric Bessin, Extension Entomologist