WASHINGTON COURT HOUSE, Ohio – A mix of a mild winter and a wet spring means just one thing for farmers: slugs.

“Slug populations increase during mild winters and flourish during wet springs,” said Jim Hoorman, owner of Hoorman Soil Health Services and former Ohio State University Extension specialist in Putnam County, Ohio. “Slugs especially thrive in no-till or cover crop fields. Slug control depends upon understanding slug biology, scouting, natural predators and effective cultural practices.”

Hoorman says there are more than 80,000 slug species, but the main pest is the gray garden slug, which lays more than 500 eggs in the spring and fall.

“Offspring from one gray garden slug can produce over 90,000 grandchildren and 27 million descendants, so slug populations can explode quickly,” Hoorman said. “Slugs mature in five to six months and may live six to 18 months with juveniles causing most crop damage, eating 2.5 times their body weight daily.

“The slug and vole population peaks every 2-5 years when winters are really cold and there is little snow. Slugs freeze out if they do not hibernate deep in the soil but often the water table also rises. So they get caught between the water table and freezing soil. Voles do not hibernate but need 40 percent more energy to survive cold winters, so without food and shelter, their numbers decline.”

According to producer John Smalley, slugs have made their presence known in Scioto County north along the Scioto River toward Columbus.

“I know farmers in that area and they’re rampant in that county and they’re attacking soybean roots,” Smalley said. “They’re abundant along the Scioto River near Lucasville and extend north toward the center of the state.”

Mike Estadt, Extension specialist in Pickaway County, said, “I’ve heard the same thing about issues in southwest Ohio as some producers are having to plant soybeans up to three times. “I’ve not heard of widespread issues here in our county, but there are always a few fields that have historically had problems.”

Slug issues have risen in Ross County. “There were areas in the county that we saw three generations of slugs this past spring,” said Chris Bruynis, Ross County Extension educator. “Some fields were replanted due to slug damage, but this wasn’t widespread and typically limited to fields with either cover crops or no-till with heavy stalk residue. Fields that had low residues or worked this spring were not as affected.”

Greg Meyer, OSU Extension specialist in Warren County, as well as Ken Ford, OSU Extension specialist of Fayette County, have not seen or heard of any concerns with slugs in soybeans or corn in their respective counties. Tony Nye, OSU Extension specialist in Clinton County said there are “just a couple minor issues with slugs but nothing major,”

“I’m not receiving calls about slugs this year. Doesn’t mean they aren’t out there,” Meyer said. “I’m just not getting any reports from Warren County farmers.”

Added Ford, “I’ve been out and about, but I’ve not seen or heard of any concerns with slugs. Actually, I’ve heard the contrary, that insect pressure has been almost non-existent. But with the timely rains over the past 10 days it could bring about some issues.”

And slugs aren’t confined in state lines. Steve Gauck, a regrional agronomy manager for Beck’s in Greensburg, Ind., said slugs affected final stands in multiple fields, especially in southern and central counties in the Hoosier state.

“We don’t see slugs every year, but they tend to show up more when it’s cool and wet early,” he said. “Part of the problem is you don’t know when or where the slugs will show up. The best remedy for slugs is warm weather and tillage. They normally move deeper in the soil once soils heat up. Tillage before replanting may help if you know there is a slug problem.”

Understanding facts about slugs, Hoorman said, can help growers understand what they’re up against.

“Slugs can survive without food for several months during hot summers, with most crop damage in the spring or fall,” Hoorman said. “Slugs are dependent upon moisture, cool conditions and lush vegetation for food and shelter. Crops usually outgrow most slug damage but during slow growing cold wet springs, slugs can decimate a crop. Fast crop emergence and growth is a key strategy to reducing slug feeding.”

And yes, slugs have natural predators, including ground beetles, fire flies, centipedes, millipedes, rove beetles, solder beetles, wolf spiders, starlings, song birds, goads, frogs and ants.

“Growers should choose cover crops that are non-hosts for slugs,” Hoorman adds. “Trap crops are not as effective in soybeans. Slugs like cereal rye, winter peas, rape and soybeans but seem to dislike crimson clover, sunflower and chicory.”