David Owens, Extension Entomologist, owensd@udel.edu
Corn
Continue scouting for cutworm activity. A report came in this week of cutworm injury to vegetables, so they are still active. Thresholds are 5% cut plants with larvae present. Dig around the base of cut plants. If an insecticide was used in furrow, larvae may be affected as they move into the treated zone. Such larvae will appear quite lethargic.
Soybean
Continue scouting for stand loss and for bean leaf beetle and other defoliator worms. Remember, thresholds are very conservatively set about 30-40% defoliation. The last several years we have evaluated herbicide pyrethroid tank mixes for efficacy and have found no significant differences in terms of yield between insecticide + herbicide vs herbicide only strips.
Small Grains
Mustang has a 14-day PHI; keep in mind as we approach harvest. Reports of armyworm activity came in this week, but it is not clear if the field was near threshold.
Alfalfa
Continue scouting for potato leafhopper! By the time hopper burn is observed, yield potential has already been lost. Leafhopper adults and nymphs have been spotted previously. A dynamic threshold table is included in our guide for alfalfa: https://www.udel.edu/content/dam/udelImages/canr/pdfs/extension/sustainable-agriculture/pest-management/Insect_Control_in_Alfalfa_-2023.pdf.