The buzz word phrase among 15-year olds today seems to be 'chilled,' or 'baffled.' Not surprisingly, some of them are baffled quite frequently! The western bean cutworm seems to be baffling entomologists in Indiana this year.
The insect made noise in neighboring states, and was found in Jasper County in Indiana before last year. But 2009 was its breakout year, with sightings and damage reports extending across at least 14 counties in northern Indiana.
Fields where the insect worked were heavily damaged. What distinguishes this insect from the corn earworm is that it typically drills four or five holes into a single ear, not one. It penetrates the shucks and can bore into the cob. Even after it leaves, it's just a highway for water, pathogens and other insects to follow. Many ears wind up with molds and sprout damage long before harvest.
Fortunately, the Herculex Bt trait controls western bean cutworm. Most other Bt traits do not. Since Smart Stax hybrids, a collaboration between Monsanto and Doe AgroSciences, contain the Herculex trait, they also offer protection against western bean cutworm. However, just introduced this year, Smart Stax hybrids were only planed on a limited acreage nationwide.
The biggest frustration right now for scouts and entomologists is where the moths are laying their eggs. Peak moth flights have been noted in many trapping locations, although entomologists suggest the peak has not yet been reached at some locations where the moths are being trapped.
The moths prefer to deposit eggs in corn before it tassels. However, because corn maturation is running ahead of schedule, much of the corn has tasseled in areas where high moth counts are being determined through trapping. It's also known that female moths have a liking for certain hybrids and certain conditions over other hybrids and sets of conditions.
What the pest managers suspect is that moths are bypassing fields that are tasseled even though they're nearby. The natural conclusion would be to look for egg hatch in fields further away from where high moth counts are observed. They may also be clumped in an area of a field that is maturing later for whatever reason. Such factors as soil compaction or varying soil types can cause one area of a field to mature and tassel later than another area in the same field.
The bottom line is that you should stay alert to reports of western bean cutworm, especially if you farm in northern Indiana. This is one pest you don't want to find out about when you pull the combine into the field. The pest will likely be gone, but evidence of his presence will be all too real based on last year's observations.