Tag Archives: slugs

Will Slugs Be A Problem in 2013?

Slugs are not a new problem, but they continue to be an unpredictable one.  It seems that they show up when and where we least expect them and never show up when and where we do.  But considering the cool and wet weather we’re experiencing, we should be on the watch.

The photo below was taken last May, 5 days after planting in a no-till field with a rye cover crop.  Stand was about half of what was expected and feeding scars could be seen on the hypocotyl and cotyledons.  When digging in the seed furrow, slugs were more often present than not.

Slug Damage Soybean

Cold, wet weather slows seedling growth; therefore reducing the plant’s ability to outgrow slug damage.  Slugs will feed on all crops, taking large chunks out of the stem and sometimes cutting the plants like a cutworm.  They feed mostly at night although I’ve seen them feeding during cloudy days (see photo below).  In general, they are more of a problem in wet, poorly drained fields or in low-lying portions of fields.  Still, we’ve seen them on hilltops.  Slug on SoybeanThey are usually a problem in no-till fields with high residue crops such as corn or grain sorghum and/or in fields the slug underneath last year’s corn stalk.  If the seed furrow doesn’t fully close, slugs will follow this “highway” and eat seedling after seedling before it emerges from the soil.

Slug Under corn residueWhat can be done about this problem?  First, scout the field before you plant, paying close attention to poorly drained or low-lying portions of the field.  If you find slugs, you have a couple of options.  One is to not plant and wait for warmer and dryer weather.  Slug damage usually disappears under warm and dry conditions.

Another alternative is to apply the slug bait/molluscicide, Deadline®, which contains the active ingredient metaldehyde.  It is sold at Deadline® M-Ps™ Mini-Pellets (colored with a blue dye) and Deadline® Bullets (dye-free).  This is the only reliable treatment that we have available.  It must be spread evenly at 10 to 40 lbs per acre over the infested area.  The product is fairly expensive, so the 10 lb rate is the most common and has worked well in my experience.  The product is not commonly stocked by local retailers, so it can be hard to find.

Will slugs be a problem?  Maybe.  Maybe not.  But, with the current weather conditions, I’d suggest scouting those slug-prone fields.

Slugs Remain in High-Residue Fields

I never expected to be writing an article on slugs in soybean in June , but this year is continuing to bring surprises.  After a generally warm winter and spring, we’ve suddenly cooled off in the first week of June.  And the slug activity in fields with a lot of residue has picked up.  Usually, our slug problem disappears by the time warmer temperatures set in.

The photo to the right was taken 5 days after planting soybean in a no-till field in Suffolk that contains lots of corn and rye cover crop residue.  Stand was only about half of what was expected and feeding scars could be seen on the hypocotyl and cotyledons.  When I dug in the seed furrow, I found slugs more often than not.  Since it was a cloudy afternoon when I was in the field, I even found slugs feeding on soybean plants that were still partially covered by residue (slugs usually only feed at night).  In an adjacent field that had not yet been planted, I found slugs on the underside of corn residue.

Will the soybean crop survive this late-season infestation?  If the crop has emerged and has a couple of leaves on it, I’d say it will.  But if you’re just planted or are now planting soybean and you’re finding slugs, I’d suggest using slug bait/molluscicide.  The only one available (other than in small packages in home improvement/gardening stores) is Deadline®, which contains the active ingredient, metaldehyde.  It is sold at Deadline®M-Ps™ Mini-Pellets (colored with a blue dye) and Deadline®Bullets (dye-free).

What if you have damage and are considering replanting?  Usually, severe damage is only in part of a field, usually wetter areas.  If this is the case and the damage is severe, you may want to consider replanted these areas.  But if it’s the entire field, I’d suggest evaluating the stand of undamaged or slightly-damaged plants, and then following my guidelines for replanted poor stands (in this issue).

For more info, see Purdue Univ. website:

http://extension.entm.purdue.edu/fieldcropsipm/insects/soybean-slugs.php or

Ohio State’s pub, Slugs on Field Crops at