The present invention discloses two biocontrol composite microbial agents, herein named PS and PSX combinations, wherein the PS combination comprises i) the PX35 strain of Bacillus spp. CGMCC 1930 and ii) the SM21 strain of Bacillus spp. CGMCC 2058, and wherein the PSX combination comprises i) the PX35 strain of Bacillus sp. CGMCC 1930, ii) the SM21 strain of Bacillus sp. CGMCC 2058 and iii) the XY21 strain of Serratia sp. CGMCC 2059 The methods for preparing the PS and PSX combinations as well as their uses in preventing and controlling soil-borne diseases of various vegetables and crops represent additional aspects of the present invention.
