To develop an efficient biocontrol antimicrobial agent of tobacco brown spot,single factor test and orthogonal test design were used to optimize the fermentation process and wettable powder(WP)was developed,and its control effect was verified.The optimal fermentation medium for antagonistic bacteria was:glucose 10 g/L,tryptone 2.5 g/L,yeast powder 2.5 g/L,NaCl 10 g/L.The optimal fermentation conditions were as follows:pH 8.0,fermentation temperature 35℃,inoculation concentration 7%,125 mL medium in 250 mL flask.The optimal formulation of WP wa...