Study on Biological Characteristics of Leaf Spot Bacteria of Zizyphus jujuba in Xinjiang and Fungicide Screening in Laboratory

Taking two strains of leaf spot bacteria of Zizyphus jujuba Alternaria tenuissima and A.alternata as materials,the effect of temperature and pH on the growth of Alternaria tenuissima and A.alternata were studied using mycelia growth speed method.The inhibition methods of mycelia growth and spore germination were tested to screen the best fungicide from 5 fungicides,in order to definite the biological characteristics and screen effective fungicides against the leaf spot pathogen of Zizyphus jujuba.The results showed that the optimum temperature for mycelial growth of he pathogen was 25~30℃ and the optimum pH ranged from 7 to 9.The 70% Mancozeb could significantly inhibit mycelium growth of the pathogen,the EC50 values were 0.053 and 0.054 g/L,and could greatly depress spore germination with inhibition,the EC50 values were 0.021 and 0.019 g/L.The 70% Mancozeb will be preferred to control leaf spot disease of Zizyphus jujube in Xinjiang.