Susceptibility of apple clearwing moth larvae, Synanthedon myopaeformis (Lepidoptera: Sesiidae) to Beauveria bassiana and Metarhizium brunneum

Abstract

Apple clearwing moth larvae, Synanthedon myopaeformis (Lepidoptera: Sesiidae) were found to be susceptible to infection by two entomopathogenic fungi: an indigenous fungus isolated from S. myopaeformis cadavers and identified as Metarhizium brunneum (Petch); and Beauveria bassiana isolate GHA. In laboratory bioassays, larvae exhibited dose related mortality after exposure to both the M. brunneum and Beauveria bassiana with 7 day LC₅₀'s of 2.9×10⁵ and 3.4×10⁵ spores/mL, respectively. Larval mortalities caused by the two isolates at 1×10⁶ spores/mL were not significantly different and 73% of the M. brunneum-treated, and 76% of the B. bassiana-treated larvae were dead 7 days post treatment, with LT₅₀'s of 5.5 and 5.1 days, respectively.

Keywords:

• Synanthedon myopaeformis
• Beauveria bassiana
• Metarhizium brunneum
• entomopathogenic fungi
• biological control

Acknowledgements

The authors are very grateful for the technical support of P. Randall and M. Gardiner (PARC, Summerland, BC) and P. Shoukouhi (ECORC, Ottawa, ON), and the support of the growers.