Amorphophallus Soft Rot Fungi Biological Characteristics And Severity Of The Occurrence Rules

Biological characteristics of the pathogen causing amorphophllus soft rot, toxicity assay of some fungicides to the pathogen, disease resistance varieties screening and effects of cultivation measures on disease resistance were carried out in this paper in order to provide the theoretical and practices foundation for the disease control.The results indicated that the pathogen causing amorphophllus soft rot in Zhuxi county of Hubei province was identified as Erwinia carotovora pv. carotovara. On PDA medium, the optimal temperature for bacterial growth of E. carotovora ranged from 25 to 35℃, with optimal pH value between 6 and 7. Through the test of carbon and nitrogen sources, Lactose and yeast extract supported the fastest growth of bacteria. The result of toxicity of different fungicides to E. carotovora showed that Streptomycin and Cyanuric acid had the best effect on the inhibition of the bacterial growth whereas Kasugamycin, Copper-hydroxide and Tiniadzo-ciprofloxacin had the lower inhibition. The resistance of twenty-one amorphophllus varieties to E. carotovora was investigated and they had significant difference. Only 4.8% varieties were high resistant, 23.8% varieties were middle resistant, and rest of the varieties were susceptible to E. carotovora. However, the resistant reaction types of some amorphophllus varieties changed during growth and harvest period. Different agricultural cultivation managements affected the occurrence and damage of amorphophllus soft rot closely. The applications of high-ridge culture, mulching and trace fertilizer were beneficial to the plant growth, increasing the resistance and reducing the occurrence and damage on amorphophllus soft rot.The above results could lay a basis for the studying on pathogenic variation of E. carotovora, high yield planting measures and integrated control of amorphophllus soft rot.