EFFECT OF SUNSCREENS, IRRADIANCE AND RESTING PERIODS ON THE GERMINATION OF METARHIZIUM FLAVOVIRIDE CONIDIA

Chemical sunscreens were incorporated into oil formulations of conidia of two isolates of the entomopathogenic fungus Metarhizium spp. and the formulations exposed to simulated solar radiation. After 2 h exposure several sunscreens gave protection as demonstrated by conidial germination after 24 h incubation on gelatin plates at 26 degrees C but only the formulations with Eusolex 8021 showed higher germination than the unprotected control after 48 h incubation. During 5 h of exposure, Eusolex 8021 failed to offer significant protection as demonstrated by conidial germination after 48 h incubation. Conidial damage was proportional to the duration of radiation received. Allowing periods of darkness between exposures did not result in decreased loss of viability. Storing conidia, after exposure to simulated radiation, for 24 h prior to germination reduced their viability.