Identification of the Pathogenic Fungus Causing Leaf Spot of Zizyphus jujubain Ningxia and Fungicide Screening in Laboratory

Taking typical leaves of leaf spot of Zizyphus jujubain Ningxia as materials,the main pathogen species of leaf spot of Zizyphus jujubain the region and effective fungicides against the disease were studied by the tissue isolation,detached leaves inoculation and inhibition method of mycelial growth.The results showed that Stemphyliumsp.were isolated from typical leaves of leaf spot of Zizyphus jujubain Ningxia and accounted for 85%of the pathogen total isolates.Among them,strain Y-14 of Stemphyliumsp.had very strong pathogenicity and was confirmed as the main pathogen species of leaf spot of Zizyphus jujubain Ningxia;Virulences of 7kinds of fungicides on pathogen were 25%propiconazole EC25%prochloraz EC1010/g Bacillus subtilis WP10%polyoxin WP250g/L azoxystrobin SC70% mancozeb WP1%phenazine-1-carboxylic acid SC,especially EC50 value of anterior 5kinds of fungicides were less than 1.0g/L,so they should be the best fungicides of leaf spot of Zizyphus jujubain Ningxia for effective biological and chemical control.