Suppose a seed salesman calls you today, knowing you don't have all your corn planted. He tries to sell you a few bags of his newest hybrid with his best GMO insect protection. His selling point is that its black cutworm moth counts are high, so it will get all moth insects, and that will be a big plus this year.
He may mean well and actually thinks he has the product you need, but he may not understand insect physiology and insect life cycles as well as you think he does. An Extension entomologist, John Obemeyer, Purdue University, helps straighten out which questions you should ask, and what things you should be aware of before making last-minute buying decision.
First, the statement that black cutworm moth numbers coming into the Midwest are high and remain high is true. A separate article on our Website explains with how you can deal with that insect.
The implication that because black cutworm moths are coming in at high numbers, all other insect moths will come in with increased numbers this year is not true, however. It's best to consider each insect on a case-by-case situation. Some of these are in the same family as black cutworm and will be controlled by certain BT traits, but the timing is off. Certain other members of the cutworm family overwinter here, and will likely be too large for the GMO-protected corn to control well.
Consider other cutworm first, including dingy, claybacked and their ugly cousins. They overwinter in Indiana as partially grown larvae. Whether their numbers are high or not is not tied to black cutworm flight numbers. Some activity was reported a week ago of dingy cutworm feeding on corn that was planted in northern Indiana. However, these species quickly become too big for control by proteins inside GMO-Bt plants.
Then there is corn earworm and western bean cutworm. It's still too early to tell what type of pressure these insects might pose this year, entomologists say. Western bean cutworm larvae will be arriving soon, but entomologists haven't begun trapping for them yet. Expect trapping to begin in mid-June.
Entomologists will also trap for corn earworm moths when the time becomes appropriate. However, it's too early to know if corn earworm or black cutworm will be a big issue in Indiana in 2011 or not.