Control Effects of Several Fungicides Against Alternaria alternata

In order to find out effective fungicides against Alternaria alternata,the indoor toxicity and field control effects of 7 fungicides against Alternaria alternata were studied with the method of mycelium growth inhibition. The results of indoor experiments showed that tebuconazole 43% SC presented the highest virulent with the lowest EC50,0.0018 mg/mL;the EC50 of Iprodione 75% WP,dimethachlon 40% WP,kangchixing No.1 45% WP,polyoxin 3% WP,mancozeb 80%WP and Thiophanate methyl 70%WP were 0.0063,0.1597,0.1891,0.3835,1.755 and 9.1313 mg/mL,respectively. The results of field experiments showed that tebuconazole 43% SC (diluted to 1/2000) exhibited the best contro1 effect. Seven fungicides in the order of control effect were tebuconazole 43% SC (diluted to 1/2000) dimethacholn 40% WP (diluted to 1/600) Iprodione 75% WP (diluted to 1/600) polyoxin 3% WP (diluted to 1/500) kangchixing No.1 45% WP (diluted to 1/800) mancozeb 80% WP (diluted to 1/500) Thiophanate methyl 70% WP (diluted to 1/700).