Resistance of Iranian Lecanicillium fungicola to Benzimidazole and Ergosterol Demethylation Inhibiting Fungicides

Dry bubble disease is one of the most important serious diseases of the cultivated white button mushroom (agaricus bisporus (lange) imbach). it is a cosmopolitan disease having a worldwide distribution. ten isolates of lecanicillium fungicola var. fungicola (preuss) zare and gams were collected from mushroom farms. sensitivity of the isolates to benomyl, carbendazim, carbendazim+iprodione and prochloraz manganese were studied. all the isolates were resistant to benomyl(ed50= 415.45-748.12 mg l^-1), carbendazim (ed50= 1123.87-1879.59 mg l^-1) and iprodione+carbendazim (ed50= 415.45-748.12 mg l^- 1). however, most of the isolates were sensitive to prochloraz manganese (ed50=1.62– 12.58 mg l^-1). as the primary source of the pathogen inoculum is casing soil and insects, stringent environmental hygiene of the mushroom houses will play a very important role in preventing and controlling the disease.