Abstract:
: Objective To identify the pathogen type and biological characteristics of leaf spot disease on Vicia faba in Jiangsu Province, and to screen chemical agents suitable for the prevention and control of this disease.
Method Pathogenic strains were obtained through tissue isolation, and identified through pathogenicity testing, morphological observation, and phylogenetic analysis based on a combined ITS and GAPDH sequence. The biological characteristics of the pathogens and their sensitivity to 10 fungicides were also determined.
Results The results indicated that the pathogen causing leaf spot on V. faba was Alternaria alternata. The isolate was suitable for growing on the optimized medium supplied with maltose, glucose, yeast extract and beef extract at 25 ℃, pH 6.0-9.0, light or 12 hour light dark alternation, and the optimal culture medium was potato dextrose agar medium or oat meal agar medium. In addition, among the 10 fungicides, sophocarpidine and fluazinam to be most effective in inhibiting the pathogenic growth with EC50 values of 0.0220 and 0.6309 mg·L-1, respectively.
Conclusion The pathogen of leaf spot disease on V. faba in Nantong city, Jiangsu province was identified as A. alternata, and clarified its biological characteristics. Sophocarpidine and fluazinam have high toxicity to this pathogen, which could be used for the prevention and control of V. faba leaf spot disease.
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