Relative humidity, temperature, and the equilibrium moisture content of conidia of Beauveria bassiana (Balsamo) Vuillemin: a quantitative approach

Isotherms for conidia of the entomopathogenic fungus Beauveria bassiana (Balsamo) Vuillemin were determined at nine constant temperatures between 10 and 50°C using saturated salt solutions. Seven different mathematical models were compared to quantify the effect of temperature and relative humidity on the equilibrium moisture content of conidia. A seven-term polynomial regression model with moisture content expressed on the fresh weight basis ( R 2=0.998, 103 df) was the best and provided no systematic deviation between observed and fitted moisture contents. This model will be a component of a geographical information system to determine the potential utility of B. bassiana for the control of grain borers in grain stores throughout the tropics.