Shelby Fleischer
We are seeing a surprising and somewhat widespread increase in fall armyworm. We also are seeing the beginning of a 2nd generation of corn borer. Southwestern sites are continuing to have earworm counts above threshold. Check fields for signs of fall armyworm feeding.
Note lots of frass associated with fresh fall armyworm feeding.
Fall armyworms (FAW)
counts are rising in multiple locations. Captures were reported in Centre, Erie, Fayette, Lehigh, and Lycoming counties, and are particularly high in several of these sites. This is a relatively early appearance of fall armyworm. The pheromone lure is not always the most sensitive, compared to the lures for the other moths we are trapping for, especially early during the immigration of this species. One idea has been that the traps are missing the early immigrants that are females (the sex pheromone lures only capture males). Perhaps later in the season, where we have in-field reproduction, we do a better job of detecting fall armyworms. I suspect that we are starting to have fall armyworm damage in corn in multiple sites. We typically see larger feeding holes, with lots of frass, often in vegetative portions of the corn. However, if the corn is silking, fall armyworm will move directly into the ear, entering the ear from the sides, top or bottom. We don’t have experimentally developed thresholds for fall armyworm. When populations rise, corn is at risk of being infested.
Corn earworm (CEW)
counts continue to be at very low levels except in the southwest. Sites in Washington and Westmoreland counties suggest a wide (5-6 day) spray interval. All other sites were below threshold for corn earworm.
European corn borer (ECB)
counts are below threshold at all sites except Bucks County, where the beginning of a 2nd generation is likely starting to emerge.
Source : psu.edu