David Owens, Extension Entomologist, owensd@udel.edu
Small Grains
Some fields in Kent County reported hitting cereal leaf beetle threshold during the week. Continue scouting for the orange-black, round larvae. Larvae are often on the upper surface of a leaf, just as eggs were a couple of weeks ago. Our threshold is 25 per 100 tillers, or 1 in 4 plants.
North Carolina is reporting spotty but widespread infestations of true armyworm. This is something they deal with only every 10 or so years. Dr. Dominic Reisig wrote an excellent post on their observations and it can be found here: https://smallgrains.ces.ncsu.edu/2018/05/true-armyworm-in-northeastern-nc-wheat-time-to-scout/. Please note, NC recommends a slightly lower worm threshold, at 6 per two square feet. Also, a possible sign is the presence of bird activity feeding on the worms.
Field Corn
Start sampling for cutworm and armyworm, particularly in fields planted with a late green grain cover crop like rye or barley. We have seen some minor leaf feeding. Our threshold is 10% leaf feeding injury and 3% cut plants. With the wet weather recently, be on the lookout for slugs, particularly in no-till fields with heavy residue and prior history of slugs.