Paper Title
Screening of Antagonistic Bacteria Capable of Inhibiting Plant Pathogens in Crucifers

Abstract
In Thailand, cruciferous vegetables are one of the most significant vegetable groups. Black rot disease is one of the devastating diseases that Xanthomonas campestris can spread on crucifers. The use of biological control agents in sustainable agriculture is growing as a result of the practice to limit the use of pesticides and the environmental residues they produce. Future sustainable agriculture will increasingly rely on the integration of biotechnology with traditional agriculture. This research was conducted to screen antagonistic bacteria capable of inhibiting the growth of X. campestris in crucifers. One hundred and six bacterial isolates were isolated from bee samples collected from different sites in northern Thailand. After testing their abilities to inhibit the growth of pathogenic bacteria, 12 isolates showed high ability to inhibit the growth of X. campestris TISTR 1100. From the hemolysis test, 9 isolated strains did not possess the capability of hemolysis. The isolates KUKPS-C3BN2, KUKPS-C3AN5 and KUKPS-C16HM4 were Bacillus spp., while the isolates KUKPS-C2AN2, KUKPS-C16HN7 and KUKPS-C17AN3 were Kluyvera sp., Enterobacter sp. and Enterobacter sp., respectively. The potential candidate-antagonistic bacteria Bacillus tequilensis KUKPS-C3AN5 and Bacillus thuringiensis KUKPS-C16HM4were employed in the development of an antagonist product and subjected to the test in field studies. Keywords - Antagonist, Bacillus, Biocontrol, Black rot disease, Crucifer, Xanthomonas campestris.