Black Cutworm & Armyworm Moth Captures Show a Big Increase

Doug Johnson, Extension Entomologist, University of Kentucky

Fig. 1 Black cutworm moth.

Black cutworm (BCW) and armyworm (AW) moths captured in the IPM traps at the UK-REC in Princeton, KY show a substantial increase for the trap week ending Friday, April 10th. In the case of BCW, 37 moths were captured when about 8 would be expected. For armyworm, 541 moths were captured when 119 would be average at this time. Captures for both of these pests are significantly greater than their rolling five- year averages. In addition, if the armyworm counts continue to increase at this rate, the population will approach the outbreak levels seen in 2006 & 2008. These are years when known pest problems either caused loss or required extra insecticidal control. See the Insect Trap Graphs on the UK-IPM webpages.

Fall Armyworm Moth Flight – Has begun to drop, but still plenty around!

Doug Johnson, Extension Entomologist

Figure 1. 2012 Capture of FAW

The second flight of fall armyworm (FAW) has begun to drop as indexed by the UK-IPM pheromone baited trap in Princeton, KY. Nevertheless, the capture for the trap-week ending Sept. 20, 2012, is still greater than the peak capture during the outbreak of 2007. (See Figure 1.) So, hopefully, we are on the downhill side of this problem, but there will still be plenty of moths to lay eggs over the next couple of weeks.

Producers, consultants and farm service personnel are still calling to report infestations and ask questions. There does not seem to be much problem with obtaining control once an infestation is found, but many folks are still not finding the infestations until considerable damage has already been done. Certainly, most callers are interested in what is coming next. Although the moth capture gives us a heads up and an indication of the level of risk, they will never tell us what is happening in a given field.

Our current weather may tend to extend the time the caterpillars are present. Our cooling temperatures are not cool enough to hamper the worms, but their development may slow down, increasing the days they will be in the damaging stage.

The crops at risk remain the same. Grass crops (pasture, hay, lawns) still remain in danger. Still, soybean problems appear to be coming from the caterpillars “marching” out of grasses in to the beans. Don’t neglect to check a field interior now and again. FAW will lay their eggs in soybeans, but grasses are by far the preferred egg laying site.

Anyone planning to plant wheat, rye, or renovate / restore any “small” grass pasture or hay field should give strong consideration to waiting for a while longer to seed. Experience tells me FAW caterpillars will be around until frost, even if not in the large numbers present now.