Pheromone trapping began for western bean cutworm moths on Monday (June 20), and sure enough some were captured that very night. This is the beginning of an extended moth emergence and flight, with their peak presence expected in the 3rd week of July, a bit later than last year as a result of the cooler April and May temperatures this year. Those in high-risk areas, i.e., sandy soils, high moth flight and WBC history, should be gearing up for field scouting of vulnerable cornfields.
Scouting should begin once moths are being captured nightly. In five different areas of a field, inspect 20 consecutive plants for egg masses which are laid on the upper surface of the top leaves of corn and/or larvae that may have hatched and crawled to the whorl and begun to feed. Usually the newest, vertical leaf is the best place to look. Young larvae need pollen to survive, and female moths are most attracted to cornfields that are just about to pollinate. Since very few, if any fields are that far developed, moths will lay eggs on whorl stage corn. Damage from larvae, as they feed deep in the whorl (attacking the tassel to get at pollen), will resemble corn borer or fall armyworm damage. Initially the damage will be subtle and not economically important, as the larvae grow so will their mouthparts and appetite. Because the proteins expressed in Herculex, Smartstax, and Viptera has shown to be very effective in suppressing this pest, scouting should not be necessary in those fields, other than for informational purposes for next years planting etc. But don't forget the refuge corn - obviously it is not protected.