Horizontal transmission of Beauveria bassiana (Bals.) Vuill
1 Factors influencing horizontal transmission of the entomopathogen Beauveria bassiana in the Colorado potato beetle (CPB) were examined through a series of laboratory studies.
2 Cadaver density, cadaver life stage, ambient temperature and conidial density were the factors manipulated.
3 Mortality and sporulation of burrowing CPB prepupae both increased significantly with increased sporulating second-instar cadaver density on the soil surface.
4 Mortality rates were significantly higher when prepupae were released into laboratory arenas containing third-instar cadavers compared to second-instar cadavers.
5 Mortality and sporulation decreased significantly as temperature increased from 15 °C to 30 °C, however, no temperature-dependent behavioural response by prepupae could be identified as a potential cause.
6 An 86.1% decrease in conidial density per cadaver had no significant effect on mortality or sporulation of prepupae, indicating that this level of environmental degradation of cadavers may not significantly reduce the probability of horizontal transmission.
Document Type: Research Article
Affiliations: Department of Biological Sciences, 306 Deering Hall, University of Maine, Orono, ME 04469-5722, U.S.A.
Publication date: 2000-02-01