What's Up With All the Earworms in Bt Corn?
This is a jointly issued article from Extension Entomologists Drs. Pat Porter (Lubbock) and Ed Bynum (Amarillo). There are large numbers of corn earworm larvae in Bt corn ears in the Texas Panhandle, and some people are spraying in an attempt to control them. The first question we are getting is what to spray, but the better question would be whether to spray. Corn earworm is usually an ear tip feeder, and on its own is seldom an economic pest of corn. However, this year we are seeing earworms doing more than just tip damage, and feeding lower in the ear. The reason(s) for this change in behavior are unknown. We have not forgotten last year though, when there was good evidence that just a little ear tip damage resulted in higher fumonisin levels. This could happen again this year, especially if the weather in August and September turns off wet and relatively cool. However, based on what we saw last year, the little bit of tip damage needed to promote fumonisin has alre...