Refresher On Cutworms
JACKSON, TENN.
You probably do not need
to worry about cutworms
if you have kept a weed
free seed bed for 2-3 weeks
prior to planting, and this is
especially true if using some
of the Bt corn technologies
(see below).
Otherwise, consider making a pyrethroid application
just before or at-planting, or within a
few days after planting.
An additional point – using Capture LFR or
another bifenthrin product as an in-furrow
spray can add some protection against insect
pests not completely controlled by seed treatments
(e.g., sugarcane beetles). I would prefer a
T-banded type application where some of the
product is applied to the “shoulders” of the seed
furrow. This should improve control of cutworms
compared with an application where 100
percent of the product is applied in-furrow.
Here is a link to an article by my counterpart,
Dominic Reisig, in North Carolina that also addresses
some at-planting insect considerations
for corn:
http://www.nccrops.com/2013/03/14/corninsect-pest-planting-considerations/
I’ve had a couple of calls related to the use of
insecticides for cutworms. No-till and late burndown
applications that allow weeds to persist in
the field are factors that increase the chances
of cutworm infestations. It is best to maintain a
clean seedbed for at least two and preferably
three weeks prior to planting. This will go a long
way in eliminating the chances of cutworm
problems, but it is sometimes easier said than
done.
A relatively low rate of a pyrethroid insecticide
is commonly suggested to prevent cutworm
damage. However, I do not recommend including
an insecticide with herbicide applications
that are made more than two weeks
in advance of planting. Tank mixing an insecticide
with an early burndown application does
not make much sense. Cutworms you kill would
have probably ‘cycled out’ before you planted
anyhow. And because you cannot expect much
residual control, there is the possibility of reinfestation
between application and planting. The
best time to make this application is just before
or at planting (or within a day or two after planting).
A few other points for your consideration:
• No insecticide seed treatments should be expected
to provide substantial control of cutworms.
• Although Bt corn and cotton traits provide
some protection against cutworms, planting
into fields that are heavily infested is a risky
business. Herculex, VT3 Pro, VT2 Pro and
SmartStax corn can reduce cutworm injury,
and I would expect the same from the Viptera
technology. In cotton, WideStrike will suppress
cutworm injury better than Bollgard II. However,
large larvae are much less susceptible to
Bt toxins. So, if populations are high enough, I
suspect any Bt technology can be overwhelmed.
• Ammo 2.5 EC and its generic equivalents
(e.g., Up-Cyde) are not labeled for use in corn or
soybean.
• Pounce 3.2 EC and its generic equivalents
(e.g., Arctic) are not labeled for use in cotton. Δ
DR. SCOTT STEWART: IPM Extension Specialist,
University of Tennessee