Identification of Phytophthora capsici in Shaanxi Province and Screening of the Fungicides against Phytophthora Blight of Pepper

By isolation culture and morphological of pathogen of pepper in Shaanxi.The isolate was identified as Phytophthora capsici Leonian;According to differential hosts,physiological race of Phytophthora capsici in Shaanxi was identified by normal identification technology;Laboratory toxicity tests of twelve fungicides to Phytophthora capsici Leonia were carried out using the methods of inhibiting mycelium growth and sporangium germination.The results showed that the isolate from Shaanxi province belonged to race3;Median inhibitory concentration for supplied fungicides of growth of the mycelium and inhibition of the sporangium germination reached significant levels;Inhibitive effect of 80% ethylicin and 959 g/L ethylicin were better than other fungicides to the growth of mycelium.The value of EC50were 252.76 μg/mL(r=0.8669)and 376.18 μg/mL(r=0.9304) respectively;The inhibition to sporangium germination of 60% dimethomorph WP and 80% mancozeb WP were better than other fungicides.The value of EC50were 317.61 μg/mL(r=0.9767) and 421.70 μg/mL(r=0.9573) respectively.60% nemesis poisoning bacteria WP and 50% iprodione WP had almost no activity against mycelium growth and sporangium germination.