Variation in the Susceptibility of Leptinotarsa decemlineata (Coleoptera: Chrysomelidae) When Reared on Different Host Plants to the Fungal Pathogen, Beauveria bassiana in the Field and Laboratory

Abstract

We determined the susceptibility of the Colorado potato beetle, Leptinotarsa decemlineata (Say) to the fungal pathogen Beauveria bassiana (Balsamo) when reared on Solanum tuberosum L., Solanum dulcamara L., Solanum carolinense L., and Lycopersicum esculentum Miller growing in both the field and greenhouse. With the exception of L. esculentum, the host plant species most suitable for L. decemlineata survival in the field produced L. decemlineata larvae least susceptible to B. bassiana. Larvae reared on different host plants in the greenhouse also varied in susceptibility to measured doses of B. bassiana conidia in the laboratory. Greenhouse-grown plants, however, appeared to be less suitable for L. decemlineata growth than field-grown plants, and host plant suitability declined with host plant age. L. esculentum declined most in suitability, and larvae reared on this host in August were more susceptible to B. bassiana in the laboratory than larvae reared on the same plants in June.