INACTIVATION OF PAECILOMYCES-FUMOSOROSEUS-CONIDIA BY DIFFUSE AND TOTAL SOLAR-RADIATION

The detrimental photic effects of natural solar radiation on the conid ial persistence of the entomopathogenic hyphomycete Paecilomyces fumos oroseus were investigated by exposing quiescent conidia either to tota l solar radiation or to its diffuse component. A given amount of UVB d iffuse radiation was found to be as detrimental, and sometimes twice a s detrimental, as the same amount of total solar radiation. The variab ility in quantity and spectral distribution of the diffuse component o f UVB solar radiation reaching the earth's surface, observed through s pectral measurements, may be responsible for the difference in biologi cal effects.