Crop growers should take extra precautions to scout their fields this spring for slugs to try to get control of these plant feeders before they attack corn and soybean plants and cause feeding injury, an Ohio State University Extension entomologist said.

Ron Hammond, who also has an appointment with the Ohio Agricultural Research and Development Center, offers his guidance in videos posted on the Plant Management Network, a nonprofit publisher of science-based crop management information for growers, consultants and other applied audiences.

Hammond is a featured speaker for April on the feeding injury that gray garden slugs can cause to corn and soybean crops.

OSU Extension and OARDC are the statewide outreach and research arms, respectively, of Ohio State University’s College of Food, Agricultural, and Environmental Sciences.

Hammond’s presentations are designed to help growers and consultants in the Midwest, Eastern and Mid-Atlantic regions manage slug problems in field crops when using no-till production, organizers said. The presentations cover basic biology of slugs and how it relates to grower practices and an Integrated Pest Management (IPM) approach to managing slug problems.

“The gray garden slug is the most damaging slug in field crops across the county,” he said. “It’s also the No. 1 slug pest problem probably worldwide.

“And this is the one causing problems in corn and soybeans and other field crops, but especially soybeans.”

The majority of problems with the gray garden slug come at crop planting in the spring, Hammond said. That is when the eggs have hatched and the juvenile slug starts to grow and reaches a size to start heavy feeding.

“And if the crop is there, they start feeding on it,” he said. “And if the crop isn’t there yet, they’ll wait for the crop and feed on it.”

In Ohio, Hammond said, this tends to occur between early and late May.

“In soybean, for example, because it’s typically planted later in spring after corn and typically emerges after juveniles hatch, it is often fed on early in its growth stage, especially during germination, which can cause a complete stand loss before growers even realize they have a problem,” he said.

General IPM recommendations Hammond suggests include:

  • Monitoring fall slug population to identify potential problem fields.
  • Using tillage in those fields if possible.
  • Planting fields with potential problems early.
  • Using practices to encourage quicker growth such as row cleaners or strip tillage.
  • Monitoring spring slug populations and injury and applying molluscicide when necessary.  A video on sampling for slug eggs is available at

Growers can use one of two available baits that contain metaldehyde (Deadline MPs and others), and those with iron phosphate (Sluggo) and a new one coming out (Ferrox), Hammond said.

Hammond’s Plant Management Network soybean and corn presentations can be viewed at: