By: Andy Michel, Curtis Young, CCA, Aaron Wilson, Kelley Tilmon, Mark Sulc
Fall armyworm caterpillars, photo courtesy of Mark Badertscher.
Last week, we discussed the possibility of a cold snap limiting any future fall armyworm outbreaks. We did have some fairly low temperatures last week—most areas had 40 to 60 straight hours of temperatures below 65oF (this was the temperature when mortality significantly impacted fall armyworm larvae). Today, several OSU extension educators have noticed a very large number of adult moths caught in our expanded trap network. As adults are migratory (often flying with winds in the atmosphere), they may be more cold-tolerant than the larvae, so it may not be surprising to still see some moths. However, we do not yet know how the cold snap affected the larvae. Fields should continue to be scouted for the presence of fall armyworm larvae at least for this week and likely until we get a significant frost. Check alfalfa, forage, cover crops, winter wheat, and even turf for damage and small larvae. As we get closer to the winter, we want to protect against any further damage that could compromise winter survival and regrowth in the spring.