Our insect development estimator, using the insect trap captures as our Biofix and current temperatures from the Princeton weather station, indicates that egg hatch has begun and small caterpillars should be present. I have not yet found any armyworms, but cutworm caterpillars have been detected in some tobacco float beds. This is a small, but timely indication that our temperature-driven estimations are on track. Producers, consultants, and scouts should begin looking for armyworm and cutworms in various crops, including small grains, corn, tobacco, and forage grasses. WARNING—we are still a bit on the early side, so most of the caterpillars may still be quite small. Cutworms large enough to cut plants may take several more days to a week before they are evident. Armyworms, especially, will avoid bright sunny conditions so one should scout in the early AM or late PM, in dense growth, and especially under surface litter remaining from last year’s crops.
Once again, remember my estimates are based on insect capture, and temperatures from the traps and weather station at Princeton (Caldwell County), KY. Other areas will vary due to differences in location. I do know that Leann Martin’s Logan County armyworm traps, though not capturing quite as many armyworm (AW) as the Princeton traps, still consistently caught more AW moths than would have been predicted by our rolling 5-year average.
Kevin Knop has three black cutworm (BCW) traps out in Wingo and Hickory, KY and Martin, TN that have consistently been a bit on the low side compared to the Princeton rolling 5-year average (CAREFUL! He is using a different trap than the University of Kentucky sites at Princeton and Logan County. The UK-IPM BCW trap in Lexington, KY is still quite a bit above the rolling 5-year average, so arrival of caterpillars in central Kentucky will be a bit later. Nevertheless it is a good time to start scouting!
Remember these model estimates are a matter of increased or reduced risk. They are not exact.
By Doug Johnson, Extension Entomologist