D3442: Novel control methods for California prionus beetle using entomopathogenic fungi

The objective of our research was to incorporate the use of entomopathogenic fungi into current management systems for control of California prionus beetle (Prionus californicus, CPB) in hops in Idaho. We screened a series of commercially available entomopathogenic fungal products based on either Beauveria bassiana or Metarhizium anisopliae against adult CPB during the summer of 2022. Of the formulations assessed, Botanigard 22WP (a product based on B. bassiana) was the most pathogenic, with nearly 100% mortality within 72 hours of exposure. Additionally, infective spores of the fungus produced by the CPB cadaver were at least as pathogenic as the formulated product. We followed these trials by developing an autodissemination trap to lure adult males to the trap using commercially available pheromone lures, expose them to the pathogen of interest (Botanigard 22WP) and let them escape after they have been exposed. Field trials are planned in commercial hop yards for early summer of 2023; beetles that escape the traps will be assessed for EPF dose received when leaving the trap. In addition, we will compare emergence patterns in fields with EPF-treated autodissemination traps to those with autodissemination traps that are not treated with EPF (control fields), to assess whether exposure to EPF via autodissemination traps alter capture history.