Study on Biological Characteristics of Alternaria alternata Caused Jujube Shrink Disease and Screening of Fungicides in Xinjiang

The effects of temperature,pH and relative humidity on mycelia growth and spore germination of three representative strains Alternaria alternata in Xinjiang were conducted indoor.And eight kinds of fungicides to the pathogen EC50 were determined using mycelia growth rate method.The results showed that the optimum temperature of the three strains were 25~30℃,the optimum pH was 6to 10;the spore germination optimum temperature was 28℃,pH was 10;with relative humidity increased,spore germination rate of three strains were also increased,when the relative humidity was 100% the spore germination up to 88.33%,95.00% and 92.00% of AKS6T-1,KRL34T11Land KS44T14Lrespectively.For the 8tested fungicides,Mancozeb 70% WP to three strains of A.alternatashowed better inhibition against mycelia growth,the EC50 was 0.074,0.098,0.034g/L,respectively.The Mancozeb 70% WP could be the primary fungicides to control jujube shrink disease in Xinjiang.