Activity of Fluazinam against Strains of Botrytis cinerea Resistant to Benzimidazoles and/or Dicarboximides and to a Benzimidazole-phenylcarbamate Mixture

Fluazinam is a new active ingredient for the control of grey mould\ belonging to the novel broad spectum phe! nylpyridinamine fungicides[ The e}ect of ~uazinam was studied on one wild type and four strains of Botrytis cinerea\ which had been isolated from vegetable crops in Greece\ and were resistant to benzimidazoles and:or dicarboximides and to the mixture of benzimidazoles "carbendazim# phenylcarbamates "diethofencarb#[ In vitro ~uazinam was found to be highly active against strains of B[ cinerea which were sensitive or resistant to benzimidazoles or exhibited multiple resistance to benzi! midazoles\ dicarboximides and to the mixture car! bendazim diethofencarb EC49 and EC84 values "concentration of active ingredient that suppresses myce! lial growth to 49 and 84)\ respectively\ of that of the fungus on fungicide!free agar medium# calculated with probit analysis\ ranged from 9[933 to 9[958 and 9[47 to 0[5 mg:ml\ respectively [ No cross!resistance was observed between ~uazinam and the market products benomyliprodione or carbendazim diethofencarb[ Preventive applications of ~uazinam in vivo completely inhibited infections of cucumber seedlings by all the above!men! tioned resistant strains of B[ cinerea[ Benomyl and ipro! dione did not e}ectively control the benzimidazole! and dicarboximide!resistant strains[ The mixture of car! bendazim diethofencarb insu.ciently controlled the strain of B[ cinerea with moderate resistance to benzi! midazoles[ The results of this investigation indicate that it should be possible to use ~uazinam as an alternative in resistance management programmes against grey mould[