Biocontrol potential of the entomogenous fungi Beauveria bassiana and Metarhizium anisopliae for tsetse flies (Glossina spp.) at developmental sites.

Spores of two entomogenous fungi, Beauveria bassiana and Metarhizium anisopliae, were mixed with sterile sand at two different concentrations (1.0 and 0.5 g/liter) and larvae of tsetse flies Glossina morsitans morsitans allowed to pupate in it, simulating field larviposition sites. One gram weight of B. bassiana-sand mixture was estimated to contain 1.4 x 10(6) spores/g and that of M. anisopliae-sand mixture 2.3 x 10(6) spores/g. Adult tsetse emerging from pupae in sand-spore mixtures suffered heavy mortalities 2-10 days postemergence. The highest mortality recorded at 1.0 g/liter was 97% for B. bassiana and 80% for M. anisopliae. Lower spore concentrations produced lower mortalities. Possibilities of biocontrol of tsetse in the field using mycopesticides at breeding sites are discussed.