Doug Johnson, Extension Entomologist, University of Kentucky
|Fig. 1 Armyworm Damge|
Don’t be surprised if the infestations are very scattered. This is typical of AW in particular and insects in general. You may be able to spot spray if you have good scouting information. AW should be controlled if scouting indicates on average 2 worms are found on 25-30% of the plants –OR- 1 worm per plant on 75% of the plants. 1st generation ECB should be controlled if 50% of the plants show fresh window pane damage. In both cases live larvae need to remain present.
If necessary, both of these insects are relatively easily controlled with a foliar insecticide application IF they are still feeding in the whorl. However, once ECB enters the stalk, foliar insecticide will not provide control. Especially for ECB and whorl feeding AW, sprays should be directed into the whorl of the plant. This is where the most significant damage will occur. Notice the AW damage in Figure 1. This damage was done when the leaves were still rolled up. Also notice that the worm is quite large. Control at this stage is not going to do much good. The damage is already done and the worm is about to become a moth and leave. Control needs to happen before this situation occurs.
Photo: S.Ebelhar, Peterson Farms.