Spatial distribution of benzimidazole resistance of Cercospora beticola Sacc. in Serbia

In order to check distribution of resistance of C. beticola isolates to benzimidazole fungicides we collected samples from four distinct geographical districts with different fungicides history in Serbia. From all localities about 40 - 50 isolates of C. beticola were collected and subjected to testing sensitivity to benzimidazoles in the laboratory. Due to RG of isolates on the discriminatory concentrations of carbendazim and thiophanate methyl we concluded level of resistance to benzimidazoles. Discriminatory concentration for carbendazim was 1 mg/l while for thiophanate methyl was 5 mg/l. Very high frequency of resistance of C. beticola isolates to benzimidazole fungicides on locality West Bačka (98 %), Srem (100%) and Moravica (97%), while on locality Rasina decrease frequency of benzimidazole resistance with 18% was established. Frequency of resistance of C. beticola populations to benzimidazoles was stable on locality where benzimidazoles were applied in the past, while on locality where they have never been applied it varies