LABORATORY SUSCEPTIBILITY OF MUSCA-DOMESTICA L. (DIPTERA, MUSCIDAE) AND BACTROCERA-TRYONI (FROGATT) (DIPTERA, TEPHRITIDAE) TO AN ISOLATE OFMETARHIZIUM-ANISOPLIAE (METSCH.) SOROKIN

The susceptibility of adult house flies, Musca domestica, and adult fr uit flies, Bactrocera tryoni, to an isolate of Metarhizium anisopliae was tested at 20, 25 and 30 degrees C. The abdomen of each insect was inoculated with a known dose of conidia in an aqueous suspension. The insects were then incubated at high humidity for 9 days. Both species of fly started to die from the disease after 4-5 days incubation at 25 degrees C and 30 degrees C and 100% mortality was reached at these te mperatures after 7-9 days. The disease developed more slowly at 20 deg rees C and the final mortality for both species was just over 50% at t he highest dose. Fewer than 25 conidia were needed to kill either spec ies at 25 and 30 degrees C at 9 days. At 20 degrees C, 5896 conidia we re needed to kill adult house flies and over 100 000 for fruit flies a t 9 days. It is concluded that M. anisopliae may be suitable for contr ol of both species in situations where chemical pesticides cannot be u sed.