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 t he formulations exposed to simulated solar radiation. After 2 h exposu re several sunscreens gave protection as demonstrated by conidial germ ination after 24 h incubation on gelatin plates at 26 degrees C but on ly the formulations with Eusolex 8021 showed higher germination than t he 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 propo rtional to the duration of radiation received. Allowing periods of dar kness between exposures did not result in decreased loss of viability. Storing conidia, after exposure to simulated radiation, for 24 h prio r to germination reduced their viability.