Slug-fest 2009
Editor’s note: This article is from the archives of the MSU Crop Advisory Team
Alerts. Check the label of any pesticide referenced to ensure your use is
included.
The
recent wet weather across the state, combined with crop residue, creates
ideal conditions for slugs. Slugs feed on cotyledons, stems, and leaves
of emerging plants. No- and reduced till fields with residue are at
greater risk for slug feeding. Slug baits with the active ingredient
metaldehyde are registered for corn and soybeans and they are highly
effective. Bait formulations (typically small pellets or granules) fall
to the soil surface and draw slugs in. Unlike contact insecticides,
which must be sprayed directly onto the pest critter, slugs do
themselves in by moving to the toxic bait and feeding. I can tell you
personally that slug baits are very effective – I treated my garden last
weekend and now have a slug killing-field.
The most common metaldehyde product is Deadline MPs (MP stands for mini
pellets). A low rate [10-12 lbs per acre] is adequate for field crops.
To help assess the reduction in a slug population before and after
baiting, I place several old shingles or boards out in the infested
field and leave them overnight. Slugs like to accumulate under the flat
surfaces during the day, and can be easily counted.
A count before and after baiting gives you a visual check that the
treatment reduced slug numbers. Deadline is sold in a 50 lb bag at
approximately $2 per pound, so a treatment runs $20 to $24 per acre.
Since plants usually grow out of slug damage once growing conditions
pick up, feeding must be pretty dramatic before a $20 per acre treatment
makes sense. If only a small part of a field is affected, consider
limiting the treatment to this area. It is sometimes tough to find
product, but in previous years Wilbur Ellis in Sparta, Helena in
Watervliet, and UAP in Sunfield carried Deadline.