Development of a Rodent Bait with Slug-repellent Properties

Since 1995, the Army’s Natural Resources Program on O‘ahu has been controlling rodents in O‘ahu’s forests to protect native plants, invertebrates, and birds. Bait longevity and attractiveness are keys to successful rodent trapping. Success is impeded when slugs interfere with bait intended for rodents. Slugs can consume all or a portion of the bait, make it less attractive to rodents via their slime, and large slugs can trigger the traps. The goal of this study was to determine whether food grade citric acid (up to 5% concentration) added to common rodent bait (i.e., commercial peanut butter and Goodnature lure) would repel slugs. We conducted several trials including where captive slugs were offered both a test (0.5-5% citric acid added) and control bait. We found slugs significantly preferred the control bait (i.e., bait without any citric acid) in the two-choice feeding experiment when the bait was Goodnature rat + mouse lure. Goodnature rat + mouse lure is the standard bait used in A24 self-resetting rat traps. The addition of citric acid may improve the longevity and attractiveness of bait to rodents in slug-inhabited environments, thereby having the potential to aid in rodent control programs