Optimizing application timing and frequency of a novel dsRNAi-based insecticide for Colorado potato beetle management

The Colorado potato beetle (CPB), Leptinotarsa decemlineata Say (Coleoptera: Chrysomelidae), is as important pest of potato, Solanum tuberosum, in the U.S. CPB management is heavily dependent on broad-spectrum insecticides, thereby stimulating an interest to identify alternative solutions. In this study, we evaluated the efficacy of ledprona, a dsRNA interference-based bioinsecticide, following different application timings and frequencies to reduce CPB populations, minimize defoliation, and protect potato yields across diverse conditions in the northern U.S.

Ledprona applied three to five times, starting when overwintered adults were present to a week after initial egg hatch, consistently provided the greatest suppression of first-generation larvae, and significantly reduced potato defoliation and yield loss. Applications initiated when larvae were abundant and most eggs had hatched, followed by one or two applications showed reduced effectiveness. While adult CPB control was inconsistent, ledprona effectively suppressed first-generation larval populations and defoliation, demonstrating its value as an effective novel bioinsecticide.

Optimal timing and frequency of ledprona applications are critical for effective CPB control in potato. Our findings indicated that the phenology of the CPB infestation will need to be monitored closely early in the season to enable proper timing of the first ledprona application. We offer practical insights for how best to integrate dsRNA-based insecticides into season-long CPB management programs. © 2025 Society of Chemical Industry.