The Investigation Of Potato Disease Of Hebei Province And Research On Major Fungal Diseases Of Potato

The disease investigation was made from July in 2001 to December in 2002 in the growth stage of potato and storage time in Chengde, Zhang jiakou, Qin huangdao, Tangshan, Baoding, Shijiazhuang, Cangzhou, Hengshui, Xingtai and Handan of Hebei province. The samples were collected, the pathogen on sample were isolated, purified and identified.Five fungi diseases of potato were found in Hebei province including dry rot of potato, wilt of potato, Rhizoctonia canker, late blight and early blight. Dry rot of potato was found in Zhangjiakou, Chengde, Baoding, Shijiazhuang and Handan. Wilt of potato was found in Tangshan, Qinghuangdao, Cangzhou and Handan. Rhizoctonia canker was discovered in Chengde, Tangshan, Shijiazhuang, Handan and Xingtai. Late blight was discovered in Weichang of Chengde, Fuping of Baoding and Wuan of Handan. Early blight was discovered in Zhangjiakou, Chengde,Qinhuangdao, tangshan, Baoding, Shijiazhuang, Cangzhou, Hengshui, Xingtai and Handan. Two bacteria diseases and five virus diseases were found, that are soft rot, scab, PVX, PVY, PVS, PVM and PLRV. Soft rot was discovered in Chengde, Tangshan, Shijiazhuang and Handan; Scab was discovered in Chengde, Tangshan, Qinghuangdao and Handan. Virus diseases of potato were discovered in Tangshan, Qinghuangdao, Baoding, Shijiazhuang and Handan.Seven species pathogens were found. That is Fursarium solani, Fusarium moniliforme, Fursarium oxysporum, Fursarium semiteatum, Alternaria solani, Phytophthora infestans and Rhizoctonia solani.The inhibition effects of 50% Carbendazim WP, 70% Mancozeb WP, 1.5% polyoxin WP, 80% Dithane M-45 WP and 40% ezomycind WP against the five main pathogens were tested at different dilutions. The result showed that 50% Carbendazim WP, 80% Dithane M-45 WP, 70% Mancozeb WP and 40% ezomycind WP had strong inhibition on Rhizoctonia solani. The inhibition effect was 100%, when the concentrations were 5 10-4g/mL, 5 10-5g/mL, 1 10-5g/rnL and 5 10-5g/rnL. 70% Mancozeb WP, 80%Dithane M-45 WP and 40% ezomycind WP had strong inhibition on Alternaria solani.The inhibition effect of 70% Mancozeb WP, 80% Dithane M-45 WP and 40% ezomycind WP on Alternaria solani was 100%, 97.4%, 98.0%, when the concentration were 4 10-4g/mL, 2.5 10-4g/mL, 5 10-5g/mL. 50% Carbendazim WP and 40% ezomycind WP had stronger inhibition than 70% Mancozeb WP and 80% Dithane M-45 WP on Fursarium spp. The inhibition effect of 50% Carbendazim WP and 40% ezomycind WP on Fursarium spp was 100%, when the concentration was 5 10-5g/mL. The inhibition effect of 70% Mancozeb WP and 80% Dithane M-45 WP on Fursarium spp exceeded 93%, when the concentration were 3 10-4g/mL, 7 10-4g/mL.Identification of mating type and physiological race were performed on 43 isolates of phytophthora infestans collected from different area of Hebei. The results showed that: (1) all of the phytophthora infestans isolates were identified as Al mating type but A2 mating type was not found in the isolates tested. (2)The distribution of physiological race of phytophthora infestans is complex, in the 43 isolates tested there are 19 different race, R10 can be overcome by all isolates.