Black cutworm moth flights picking up in the Midwest
With unseasonably cold temperatures in the Midwest finally relenting, black cutworm (BCW) moth flights are increasing, resulting in some significant moth traps in southwestern and west-central Illinois. So what does it mean for the likelihood of a BCW outbreak this spring?
"We can say when they arrived and whether they were earlier or later than last year, but outside of those relevant comparisons, it's a crapshoot to know whether there will be significant damage," says Kevin Steffey, Extension entomologist at the University of Illinois. "But with the moth flights gaining in intensity at the same time as the planters are beginning to roll, we may be setting ourselves up for a situation where black cutworms will be hatching and feeding when corn is vulnerable."
Growers in southern regions of the Midwest should also be on alert for egg hatch as a result of moth flights that occurred in mid- to late-March. Unless larvae hatched from eggs during the recent cold snap and were exposed to below-freezing temperatures, Steffey says that BCW eggs most likely survived. His opinion matches the results of an experiment conducted by Marlin Rice, Extension entomologist at Iowa State University.
Steffey says BCW moths are seeking favorable habitats to lay eggs, primarily fields with winter annual or perennial weeds, and perhaps crop residue. Field conditions are important, he adds, saying BCW will look to lay eggs wherever "you've got a green carpet of weeds."
Rescue insecticides like organophosphates and pyrethroids are effective against BCW, so long as there is no crusting of the soil and the insecticide does not get tied up in field residue. However, a preventive approach may be an easier way of addressing potential BCW problems.
"It depends upon how diligent growers are with scouting and how quickly they recognize an infestation," Steffey says in a Dow AgroSciences report. "At the point and time that growers need to be scouting for black cutworm, they often are turning their attention to planting soybeans and donâ€™t have a lot of time for scouting cornfields.
"If a grower is going to use something preventive, the best approach is probably a corn hybrid with a trait that will control black cutworm. If you intend to use in-plant traits for control of European corn borer and southwestern corn borer, you can select a hybrid that also provides control of black cutworm," he adds.
Lyndall Dallas, product development specialist for Dow AgroSciences, says corn growers who plant hybrids containing either the HERCULEX I Insect Protection or HERCULEX XTRA Insect Protection traits have built-in protection against BCW. However, neither YieldGard nor Agrisure in-plant traits are labeled for protection against BCW.
"Many growers in the Southern regions of the Corn Belt where black cutworm is prevalent are already using an in-plant trait for European corn borer protection. They can get the added protection against black cutworm with HERCULEX I, as well as protection against western bean cutworm and fall armyworm," Dallas says. "For those growers who also need corn rootworm protection, they should use HERCULEX XTRA for both above- and below-ground protection."