Agriculture Online
04-26-07
Black cutworm moth flights picking up in the Midwest
Considerable crop damage potential exists
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 belowfreezing 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 don 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."
Finally, Dallas says growers should not rely solely on seed treatments for control
of BCW. Ohio corn producers experienced heavy BCW pressure last year, and
Ohio State University Extension reported that seed treatments did not provide
adequate activity against BCW.