Robert Wright, extension entomologist at the University of Nebraska-Lincoln Institute of Agriculture and Natural Resources, and Justin McMechan, crop protection and cropping systems specialist, recently shared their advice for corn producers as insects begin to emerge across the country.
Early season damage from insects, such as cutworms, wireworms, white grubs and wheat stem maggots are not uncommon, according to the experts. Wireworms and white grubs feed underground, while cutworms feed on or below the soil surface. For this reason, the experts advise corn producers to look for plant damage and then dig in soil around their plants to verify which insects pose threats.
In the case of wheat stem maggot, these insects feed above ground. This means that damage caused by them may be visible to the naked eye without needing to dig within the soil. That being said, the experts still advise producers to examine plants that look injured to verify that wheat stem maggots are the culprit.
Cutworm and other insects may still cause issues for corn producers, even if seed is treated with insecticide before planting. Generally, a postemergence “rescue” treatment can be used if cutting is observed on 3 to 5 percent more plants and the worms are one inch or less in length.
The experts note that the odds for damage diminish with the warming of the soil. More information and tips can be found by visiting the UNL Extension website.