陕西辣椒疫病病原鉴定及其防治剂的室内筛选

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

通过对陕西辣椒疫病病原菌的分离培养和形态学观察,将引起陕西辣椒疫病的病原菌鉴定为辣椒疫霉(Phytophthora capsiciLeonia);利用一套鉴别寄主,通过常规抗病性鉴定技术,对陕西辣椒疫霉菌进行生理小种鉴定,并采用菌丝生长抑制法和孢子囊萌发抑制法测定了12种常用的防治剂对辣椒疫霉菌的毒力。结果表明:陕西辣椒疫霉菌分离物属于生理小种3;不同供试药剂对菌丝生长和孢子囊萌发的抑制中浓度差异达到极显著水平;对辣椒疫霉菌菌丝生长抑制效果较好的是辣椒病菌清和活康壮,EC50分别为252.76μg/mL(r=0.8669)和376.18μg/mL(r=0.9304);对孢子囊萌发抑制效果较好的是69%烯酰吗啉WP和80%代森锰锌WP,EC50分别为317.61μg/mL(r=0.9767)和421.70μg/mL(r=0.9573);60%椒霸菌毒克星WP和50%扑海因WP对辣椒疫霉菌菌丝生长和孢子囊萌发几乎没有抑制作用。

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. 61μg/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.