MUTANTS OF <i>METARHIZIUM ANISOPLIAE</i> WITH INCREASE VIRULENCE TOWARD MOSQUITO LARVAE

Abstract

A wild-type strain of Metarhizium anisopliae (Metsch.) Sorokin, an imperfect fungus, killed 76% of Culex pipiens pipiens larvae within five days after spore administration. A spontaneous mutant strain was selected whose LD 50 was less than half that of the wild type, and whose LT 50 was one day faster. This mutant also showed early, dense sporulation, rapid in vitro spore germination, and enhanced production of destruxins. It is probable that at least one of these additional characteristics is related to the mutation to hypervirulence.