Studies on the prolonged storage of Metarhizium anisopliae conidia. Effect of temperature and relative humidity on conidial survival and virulence against mosquitoes
Journal of Invertebrate Pathology
Unformulated conidia of three strains of Metarhizium anisopliae were stored at four temperatures (viz., 37°, 26°, 19°, and 4°C) at each of six relative humidities (RH) (viz., 0, 12, 33, 53, 75, and 98%) and at −20°C at 0% RH. Conidial viabilities and virulence against two species of mosquitoes were determined at various intervals over a 2-year period. Conidia were found to survive longest when moderate temperature-high RH (26°C–97% RH or 19°C–97% RH) or low temperature-low RH (4°C–0% RH) were used, while intermediate RH values between 33 and 75%, depending upon the strain, were most lethal. As the temperature declined from 37° to 4°C at nearly all RH values the longevity of spores increased. Conidia remained highly virulent under favorable storage conditions for at least 18 months against Culex pipiens pipiens or 12 months against Anopheles stephensi larvae.
Daoust, R.A. and D.W. Roberts. 1983. Studies on the prolonged storage of Metarhizium anisopliae conidia. Effect of temperature and relative humidity on conidial viability and virulence against mosquitoes. J. Invertebr. Pathol 41:143 50.