Abstract:

In order to investigate the long term efficacies of fumigants on two soil-borne pathogens and their influences on soil microbial community recovery, the authors studied the efficacies of chloropicrin (PIC) 40 mg/kg, dimethyl disulfide (DMDS) 40 mg/kg and PIC+DMDS (8+32) 40 mg/kg on Fusarium spp. and Phytophthora spp., as well as their influences on soil microbial community by using plate count, soil microbial biomass carbon, soil microbial biomass nitrogen and BIOLOG method. The results indicated that after 98 days fumigation, chloropicrin (PIC) 40 mg/kg still had significant efficacies in controlling Fusarium spp. and Phytophthora spp., while its influences on soil microbial community had recovered to control level. PIC+dimethyl disulfide (DMDS) (8+32) mg/kg was more effective in long term Fusarium spp. and Phytophthora spp. suppression compared with DMDS 40 mg/kg. 28 days after fumigation, influence of PIC+DMDS (8+32) mg/kg on soil microbial community diversity had recovered to control level. In line with its lower efficacies against soil-borne pathogens, DMDS 40 mg/kg had little influence on soil microbial biomass and soil microbial community diversity.