Protection of Potatoes and Mortality of Wireworms (Agriotes obscurus) With Various Application Methods of Broflanilide, a Novel Meta-Diamide Insecticide

Pest Elaterids of North America: New Insights and Opportunities for Management

The larval stages of click beetle (Coleoptera: Elateridae) species, several of which are serious agricultural pests, are called wireworms. Their cryptic subterranean habitat, resilience, among-species differences in ecology and biology, and broad host range, as well as the lack of objective economic injury thresholds, have rendered wireworms a challenging pest complex to control. Significant progress has been made in recent years, introducing a new effective class of insecticides and improving species identification and our understanding of species-specific phenology, chemical ecology (i.e., adult sex pheromones and larval olfactory cues), and abiotic and biotic factors influencing the efficacy of biological control agents. These new developments have created opportunities for further research into improving our risk assessment, monitoring, and integrated pest management capabilities.

Burkholderia spp.-based biopesticide controls wireworms (Coleoptera: Elateridae) in potatoes

Wireworms (Coleoptera: Elateridae) are economically significant pests of potatoes (Solanum tuberosum), damaging the marketable portion of the crop by feeding and tunneling into tubers. While conventional potato growers use the few registered synthetic insecticides to control wireworms, certified organic growers are left with less options due to the limited effectiveness of the available insecticides. Biologically derived pesticides provide an additional alternative for both systems. Certain gram-negative proteobacteria, such as Burkholderia spp., possess insecticidal compounds. However, very little is known about their efficacy on wireworms. From 2018 to 2021, we conducted experiments in Virginia to assess the efficacy of a Burkholderia spp.-based commercial pesticide, Majestene, as a wireworm control in potatoes. In a lab experiment, soil drench application of this insecticide at a rate of 66 g a.i. per 1 liter resulted in 30% wireworm mortality and significantly reduced wireworm feeding damage on potato tubers. In the field, in-furrow applications of Burkholderia spp. at a rate of 17.66 kg a.i. per ha significantly reduced wireworm damage to tubers in 2 of 7 field experiments conducted. By comparison, the commercial standard insecticide, bifenthrin, significantly reduced tuber damage in 3 of the 7 field experiments. Our study demonstrates the prospect for proteobacteria-derived insecticides for control of wireworms and potentially other soil-dwelling insects. In conclusion, findings present growers with another option to combat wireworm pressure, especially in organic systems.