New Codling Moth Pathogens: Progress Report

Organic apple production in Washington state faces growing risk due to codling moth resistance to existing biopesticides, particularly granulosis virus. This project focuses on identifying and developing new fungal pathogens as biological control tools. Researchers isolated and cultured three entomopathogenic fungi from codling moth populations in commercial orchards: Beauveria bassiana, Metarhizium robertsii, and a Hirsutella/Ophiocordyceps species. Laboratory and field assays confirmed that B. bassiana and M. robertsii are highly effective, causing over 90% mortality in codling moth larvae after selective breeding for increased virulence. The team also developed a multiplex screening tool to accelerate pathogen identification. Ongoing work includes refining pathogen selection for traits such as field persistence and mass production potential. If successfully developed into biopesticides, these fungal strains could provide urgently needed alternatives for organic pest management, reduce reliance on existing control methods, and help maintain the economic viability of Washington’s organic apple industry.