Studies On Phytophthora Capsici's Biological Characteristics And Chemical Control Against Phytophthora Blight Of Pepper

By using of selectivity culture medium and microscope, 19 Phytophthora capsici strains have been collected and identified in the experiments, which come from Beijing city, Shanxi Province, Guangxi Province, Guangdong Province, Nanjing city and Changsha, Heng yang, Liuyang, Wangcheng, Chenzhou, Loudi, Zhuzhou, Changde, Yiyang.Yueyang, Hunan Province, respectively. Then, the Phytophthora capsici's biology characteristic were studed, which including the suited PH for growth, the best illumination, temperature and culture midium condiction of sporangium's production, and the difference between their Pathogenicity.The results revealed, Phytophthora capsici grow best on the oat culture midium when PH between 6 and 7,and it's growth was restrained obviously when PH was above 9. Among the three illumination disposals, 12 hours one day was by far the best way,followed by 24 hours one day,and zero hour one day, the worst. The quantity of sporangium's production was low when growed in Phytophthora capsici's suited temperature(24℃- 28℃) scope ,but when it come to 21℃,30℃ and 33℃,the quantity was higher,which means there maybe lay certain balance between it's nutrient growth and generative growth in these temperature.The results of their Pathogenicity identify experiments improved that there were differences among their Pathogenicities. Among them, Pathogenicities of strains Phyl and Phyl2 were perferable and Phyl2 the best, however, Phy3 and Phyl4 were the worst.There weren't marked differences among the other 15 strains.Results from vivo and virto experiment were similar.15 fungicides' individual virulence identify and biunited virulence identify were studied in lab, including four new fungicides 25% Amisida SC, 56%AF-117SC, 25%AF-12946 SC , 53% Gold Ridomil-MZ WG, besides, different strains' tolerance to the fungicides were studied and the relativity between temperature condition and effects of individual virulence identify were researched. Then, we studied the relativity between control time and contorl effects, control ways and control effects. Last, control effects test in the field were carried out.The results revealed, four new fungicides 25% Amisida SC, 56%AF-117SC, 25%AF-12946 SC , 53% Gold Ridomil-MZ WG were effective to Phytophthora capsici in individual virulence identify experiment, furthermore. They show good coadjutant capability to other fungicides, meaning their wonderful outlook of application . Results from potten plant test and field one also agreed with the conclusion. 72.2%Pulike SC, 75%Chlorothalonil WP, 52.5%Yikuajing WP also show preferable effects. There were not relativity between different strains' tolerance to the fungicides and their Pathogenicities , the temperature condition,the control time and the control way had direct influence to fungicides'contorl effects.