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 (Ba lsamo) Vuillemin were determined at nine constant temperatures between 10 a nd 50 degreesC using saturated salt solutions. Seven different mathematical models were compared to quantify the effect of temperature and relative hu midity on the equilibrium moisture content of conidia. A seven-term polynom ial regression model with moisture content expressed on the fresh weight ba sis (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 compon ent 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. (C) 2001 Elsevier Science Ltd. All rights reserved.