Sensitivity of Sclerotinia sclerotiorum to strobilurin fungicides in Slovakia.

Rapeseed isolates of Sclerotinia sclerotiorum (Lib.) de Bary 1884 from the Nitra Region of Slovakia were investigated for their in vitro sensitivity to azoxystrobin and picoxystrobin; and for determining their EC50 value. The growth of S. sclerotiorum was evaluated on a PDA medium amended with the selected fungicide´s active ingredient at 4 different concentrations – 0.08, 0.83, 8.33, and 83.30 ppm. The overall mean EC50 values for azoxystrobin and picoxystrobin were 2.73 ppm and 3.12 ppm, respectively. The majority of the isolates had resistance factors up to 20, which suggests a shift in the S. sclerotiorum population sensitivity towards the resistance. [ABSTRACT FROM AUTHOR]