By: Bruce Potter
Several reports of true armyworm infestations have come in from a fairly wide area in southern and into west central Minnesota. There are likely fields in other geographies that saw armyworm moth immigrations. Based on the descriptions of larval size and moth captures, this current round of infestations is likely related to moths arriving with a series of storms about three weeks ago.
Subsequent winds from the south continue to bring armyworm moths into Minnesota. Moths from these later flights have sought out and laid eggs in live, dense grass stands so problems can continue to crop up for a while.
Most of the current reports have been from corn planted into a rye cover crop but other grass crops can also be affected.
Check lodged areas first. True armyworms prefer to feed on grasses but sometimes soybeans planted into a rye cover can be attacked by starving armyworms. Information on scouting tips and thresholds can be found at corn pest management armyworm.