Further studies in increased sensitivity to N‐phenylanilines in benzimidazole‐resistant strains of Botrytis cinerea and Venturia nashicola

The ring-substituted N-phenylanilines, N-(3-chlorophenyl)aniline (MC-1) and N-(3,5-dichlorophenyl)aniline (MC-2) were tested for their antifungal activity against Botrytis cinerea Pers. ex Fr. and Venturia nashicola Tanaka et Yamamoto. In both fungi, increased sensitivity to MC-1 and MC-2 was clearly observed in «highly carbendazim-resistant, diethofencarb-sensitive» (HR, S) phenotypes. Sensitivity was low in «carbendazim-sensitive, diethofencarb-resistant» (S, R) and «intermediately carbendazim-resistant, diethofencarb-resistant» (IR, R) strains. On cucumber cotyledons, other strains of B. cinerea, possessing the phenotype «highly carbendazim-resistant, diethofencarb-resistant» (HR, R) were not controlled by either MC-1 or MC-2. Response to MC-2 was also examined using random ascospore progenies from V. nashicola crosses. In these progenies, high-level carbendazim resistance and MC-2 sensitivity always segregated together. Sensitivity to MC-2 is controlled by a single gene which is either identical to or very closely linked to one conferring high-level resistance to carbendazim