Laboratory toxicity tests of twelve kinds of fungicides to Phytophthora capsici

Laboratory toxicity tests of twelve fungicides to Phytophthora capsici were carried out using the methods of mycelium growth and sporangium formation.The results showed that the effects of these fungicides were significantly different in inhibiting the growth of mycelium and the formation of sporangium of P.capsici.Among all these fungicides tested,the inhibitive effect of 50 % dimethomorph WP and 68 % M-metalaxyl MZ were better than other fungicides to the growth of mycelium.The inhibition rate equation to the mycelium growth respectively were as:y=4.4346+0.7598x and y=2.3933+1.3049x,and the value of EC_50 were 5.55 g/mL and 6.66 g/mL respectively.The inhibition to the sporangium formation of 50 % dimethomorph WP and 72.2 % propamocarb were better than other fungicides.The inhibition rate equation respectively were as:y=2.3933+1.3049x and y=2.2695+1.3036x,and the value of EC_50 were 99.45 g/mL and 124.34 g/mL respectively.