P-065 - Potential of the new agent, Bacillus amyloliquefaciens R8-25, on control weeds and its characteristics

Endophytic Bacillus amyloliquefaciens R8-25 obtained from banana was evaluated the potential on control of Amaranthus spinosus (AS) and Bidens pilosa var. radiata (BP). The seed germination test indicated when the concentration of fermentation liquid diluted with 10-fold or higher could inhibit the seed germination of AS and BP completely; meanwhile, the seed germination of Oryza sativa (OS) could be inhibited by 5-fold diluted fermentation liquid completely. Comparing the effect of carbon/nitrogen sources on R8-25 growth, the fructose, mannitol, NH₄Cl and glutamate are best. Filtrates from certain carbon/nitrogen source cultured R8-25 could promote inhibition rate of seed germination of BP. Furthermore, R8-25 fermentation liquid mixed with acetic and citric acid had synergistic effect on increasing inhibition rate of seed germination of BP. For plant test, 5-fold dilution of the fermentation liquid could cause 75.0% and 82.5% damage on 2 weeks old of AS and BP respectively, based on drenched method. However, the fermentation liquid did not show any effect on OS plant. The stage of BP had different sensitivity to fermentation liquid, especially, the youngest plant (cotyledon stage) showed most sensitivity. Although fermentation liquid of R8-25 did not affect the chlorophyll content of BP, it could damage the root system. For compounds of fermentation liquid analysis, ethyl acetate layer was more efficacy than water layer on inhibiting seed germination and plant growth of BP. One peak in ethyl acetate layer was considered as effective compound based on HPLC analysis.