A Watchful Eye For Slugs
JACKSON, TENN.
Looking at one of my corn
trials was a reminder that
slugs may be a bigger
issue than usual this year.
Cold damp weather coupled
with slow seedling growth is a
recipe for slug problems.
Below are some things to keep in mind when
thinking about slugs.
Slugs will feed on leaves and the stems of all
major row crops, sometimes cutting the plants
like a cutworm. Begin a wimpy seedling, cotton
is pretty sensitive to slug feeding, but corn and
soybean are also at risk.
Slugs feed mostly at night,
but like I observed today,
they can also be found feeding
during the day in cloudy
and cool weather. Mysterious
holes in the leaves are a sign
of slugs. They will often be
hidden under debris and
clumps of soil during the
day. Plants may be cut similar
to cutworm injury.
Slugs are almost exclusively
a problem in reduced
tillage fields but could be a
problem in conventional
fields that had very heavy
weed cover the previous fall.
Because they tend to occur
where there is a lot of
residue, be especially alert
following a previous crop of
corn or sorghum. They also
tend to be worse in low, wet
areas of the field. And these areas are the same
spots where seedlings tend to grow slowly.
Planting in wet fields, where the seed trench
does not close completely, creates a slug highway
down the row. In my experience, this creates
the worst problems because slugs will feed
all day long in the seed furrow, even before the
seedling has completely emerged.
Insecticides seldom provide effective control of
slug infestations. They slough off the nastiest of
chemicals.
The only reliable treatments are baits that
contain metaldehyde. Deadline M-Ps is a bait
from Amvac that contains 4 percent metaldehyde.
The Deadline M-Ps label allows a use rate
of up to 40 lb per acre in field crops, but it is
pretty expensive, so the standard rate is 10 lb
per acre. Deadline M-Ps is a pellet and must be
spread relatively evenly across the field, which
requires some planning. Also, this product is
not typically carried in stock by local retailers.
Be sure to place you order as quickly as possible
if you decide treatment is needed.
Treatment is recommended when slugs
threaten to reduce stands below acceptable levels.
I know that is a “weak” threshold, but it is
really the best I can do. You can tolerate more
slugs as seedlings get larger and has the
weather warms (and dries). Δ
DR. SCOTT STEWART: IPM Extension Specialist,
University of Tennessee