Indianapolis, Indiana
April 26, 2007
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 relative 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 said that BCW eggs most likely
survived.(1) His opinion matches the results of an experiment
conducted by Marlin Rice, Extension entomologist at Iowa State
University.(2)
Steffey says BCW moths are seeking out favorable habitats to lay
eggs, primarily fields withwinter annual and 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,” he says. “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.”
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 the Ohio State University
Extension reported that seed treatments did not provide adequate
activity against BCW.(3)
“If you plan to use an in-plant insect trait, it makes sense to
use HERCULEX,” Dallas says. “It provides protection against
black cutworm, and essentially leaves you with one less insect
to worry about.”
1)
www.ipm.uiuc.edu/bulletin/article.php?id=686
2)
www.ipm.iastate.edu/ipm/icm/2007/4-16/bcw.html
3)
http://corn.osu.edu/story.php?setissueID=170&storyID=1004
®HERCULEX is a trademark of Dow AgroSciences LLC
®YieldGard is a registered trademark of Monsanto Company.
™Agrisure is a trademark of Syngenta Crop Protection, Inc.
HERCULEX Insect Protection technology by Dow AgroSciences and
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