Promoting natural suppression of slugs using local parasitic nematodes

Project Overview

Project Type: Graduate Student
Funds awarded in 2022: $15,000.00
Projected End Date: 11/10/2024
Grant Recipient: University of Delaware
Region: Northeast
State: Delaware
Graduate Student:
Faculty Advisor:
Dr. Michael Crossley
University of Delaware


  • Agronomic: corn, soybeans


  • Crop Production: cover crops, no-till
  • Education and Training: extension
  • Pest Management: biological control, field monitoring/scouting
  • Sustainable Communities: sustainability measures

    Proposal abstract:

    As more farms in the US Northeast adopt conservation agriculture practices such as reduced tillage and cover cropping, new challenges to pest management continue to emerge, reinforcing the axiom that “no good deed goes unpunished”. Slugs, particularly the gray garden slug (Deroceras reticulatum) and the marsh slug (Deroceras leave) have emerged as prominent pests of corn and soybean under no-tillage systems in the United States. Chemical control using molluscicide baits is the most common control method. However, these baits are expensive to apply, ineffective in many field conditions, and harmful to humans and wildlife. Biological control represents an important alternative approach to slug management for growers practicing conservation agriculture. Slug-parasitic nematodes can be potent biological control agents, and one species is already being deployed in Europe. However, slug-parasitic nematodes are so far unknown and unutilized in the US Northeast. This is because there are only a few “locally” isolated strains in the United States (from the West Coast) and importation of such species is highly restricted. Therefore, the proposed research aims to: 1) Identify species of slug-parasitic nematodes and their prevalence in no-till corn and soybean production systems in Delaware and Maryland, and 2) Determine the effectiveness (% mortality induced, impact of infection on slug feeding behavior) of these slug-parasitic nematodes against slugs. This represents an important step toward developing an effective and sustainable slug management strategy for Northeastern grain production and the project will provide significant training for the student committed to promoting integrated pest management in the USNortheast.

    Project objectives from proposal:

    Objective 1: Identify species of slug-parasitic nematodes and their prevalence in no-till corn and soybean production systems in Delaware and Maryland

    Objective 2: Determine the effectiveness of slug-parasitic nematodes against gray garden slugs and marsh slugs:

    2a) Determine percent slug mortality caused by different slug parasitic nematode species using different concentrations (lethal doses) under laboratory conditions

    2b) Define the amount of time it takes for nematode-infected slugs to stop feeding

    Any opinions, findings, conclusions, or recommendations expressed in this publication are those of the author(s) and do not necessarily reflect the view of the U.S. Department of Agriculture or SARE.