Study on the conidial dispersion of Beauvaria bassiana (Balsamo) VuillemiN (Deut.: Moniliaceae) in date by larval and adult stages of Saw toothed Beetle, Oryzaephilus surinamensis L. (Col.: Silvanidae)

Beauvaria bassiana (Buls.) Vuill. is one of the Sawtoothed beetle, Oryzaephilussurinamensis (L.), pathogens in date stored condition. The ability of differentdevelopmental stages of the beetle to disperse the fungus primary inoculums in three date cultivars Sayer, Zahedi and Deiri were studied. The individual dispersal functions asspore dispersal power and cross infestation rate as spore dispersal rate were calculated.Results showed that there were significant differences in spore dispersal ability by larvaland adult stages and in three studied date cultivars. The slope of individual dispersalfunctions for different developmental stages were negative that indicating the reduction of primary inoculums of pathogen by distance. The rate of primary inoculums transmissionwas reduced by time also. So, the maximum of dispersal occurred in first days ofinoculation. Maximum spore dispersal occurred on Deiri and its amount was similar inSayer and Zahedi. The adults were more effective on dispersal of primary inoculums ondate than the larvae. Conidial dispersion on date wasnt aggressive and the fungi conidiawere dispersed on all sites of stored date. Dispersal rate by adults was faster than larvae.