True Armyworms

Bryan Jensen, IPM Program

True Armyworm is yet another insect to keep on your radar over the next few weeks. There hasn’t been any report of damage in Wisconsin or to the states to our south but the WDATCP has reported sporadic, low intensity flights in their blacklight trap network. However, corn is emerging at a fast pace and it would be worthwhile to spot-check those corn fields that have the greatest potential for damage. 

The spring migration pattern of true armyworm is much the same as black cutworm adults. However, you can’t necessarily draw damage comparisons on one based on what happened with the other. Likely armyworm damage scenarios may include lush grassy weed growth in emerging corn fields and especially corn that is no-tilled in alfalfa or a grass cover crop like rye. Armyworms are certainly a potential problem in spring or fall planted small grains.   Be sure to spot check some of these fields. 

Photo 1: True Armyworm Larva