Compatibility of Beauveria bassiana with selected fungicides and herbicides

The effects of 6 fungicides (chlorothalonil, maneb, thiophanate-methyl, mancozeb, metalaxyl+mancozeb and zineb) and two herbicides (diquat and glufosinate-ammonium) used commercially in potato fields were evaluated in vitro on Beauveria bassiana (Balsamo) Vuillemin, a fungalpathogen of the Colorado potato beetle, Leptinotarsa decemlineata (Say). All 6 fungicides tested along with the herbicide glufosinate-ammonium inhibited B. bassiana mycelial growth and sporulation. However,the 2nd herbicide tested, diquat, had no noticable effect on B. bassiana mycelial growth and sporulation. Remarkably, diquat synergized the insecticidal activity of B. bassiana in the simultaneous treatments on Colorado potato beetle adults and caused 50-76.6% mortality. [ABSTRACT FROM AUTHOR]