Toxicity of a Novel DsRNA-based Insecticide to the Colorado Potato Beetle in Laboratory and Field Trials

Background: The Colorado potato beetle, Leptinotarsa decemlineata (Coleoptera: Chrysomelidae) is one of the most notorious pests of the potato, Solanum tuberosum. Potato beetles are capable of developing resistance to various insecticides in relatively few generations. Novel and effective means of controlling Colorado potato beetle populations are constantly required to protect potato crops and prevent loss of yield. The knockdown of gene function through ribonucleic acid interference has been demonstrated in Colorado potato beetles, suggesting the use of this technology as a means of beetle management. A novel double-stranded RNA-based insecticide with the active ingredient, ledprona, has been tested in variable dose laboratory bioassays, followed by field studies.

Results: Exposure to ledprona resulted in both increased beetle mortality and decreased foliage consumption in all four instars and adult beetles. Effects decreased from earlier to later life stages. No ovicidal activity was detected. Onset of mortality was slower compared with existing chemical insecticides. Nevertheless, field applications of formulated ledprona to potato plots resulted in their protection comparable with that provided by spinosad and chlorantraniliprole.

Conclusion: Based on the results of this study, formulated ledprona has attributes to become a useful tool in controlling Colorado potato beetle populations that is likely to be a good fit in integrated pest management protocols. © 2022 Society of Chemical Industry.