Sensitivity of Sclerotinia sclerotiorum to strobilurin fungicides in Slovakia

Rapeseed isolates of Sclerotinia sclerotiorum (Lib.) de Bary 1884 from Nitra Region of Slovakia were investigated for their in vitro sensitivity to azoxystrobin and picoxystrobin; and determining the EC50 value. The growth of S. sclerotiorum was evaluated on PDA amended with the selected fungicide´s active ingredient at 4 different concentration – 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. Majority of isolates had a resistance factors up to 20, that suggests the shift in S. sclerotiorum population sensitivity towards the resistance.