An Evaluation of Cultural and Chemical Control Practices to Reduce Slug Damage in No-till Corn

SIMPLE SUMMARY: Slugs are the most damaging non-arthropod pest of corn grown in no-tillage systems in the US. The decaying plant residue on the soil surface provides food, shelter and optimum microenvironmental conditions for slug development and survival. In this study, we evaluated several cultural practices to reduce the risk of slug injury and the efficacy of different rates and application patterns of rescue treatments. Corn planted with row cleaner devices to remove surface residue over the seed row and starter fertilizer to enhance seedling growth, together reduced slug activity around emerging plants and provided more favorable conditions for plants to outgrow and tolerate feeding damage. We found that reduced rates of molluscicide baits applied as a directed band over the seed row and broadcasted solutions of urea-based nitrogen applied at night provided effective control as rescue treatments. Practical considerations of these treatments are discussed, as well as changes in weather patterns and current planting practices that have had contrasting effects on slug populations and their potential damage. ABSTRACT: Slugs, primarily the gray garden slug, Deroceras reticulatum (Müller), are the most damaging non-arthropod pest of corn grown in conservation tillage systems in the US. These mollusks favor decaying plant residue on the soil surface, which provides food, shelter and optimum microenvironmental conditions for their development and survival. Here, field plot experiments evaluated several cultural and chemical control practices to suppress slug activity and feeding injury during early seedling growth. The use of row cleaners to remove surface residue over the seed row and starter fertilizer applied different ways during planting significantly reduced the percentage and severity of plants damaged by slugs by negatively affecting their activity around emerging seedlings and providing more favorable conditions for plants to outgrow and tolerate feeding injury. As rescue treatments, reduced rates of a 4% molluscicide bait applied as a directed band over the seed row, and broadcasted solutions of urea-based nitrogen applied under calm winds at night provided effective slug control. Practical considerations of these treatments are discussed, as well as changes in weather patterns and current planting practices that have had contrasting effects on slug populations and their potential damage.