| Endophytic bacillus subtilis strain Y13, which was obtained from oil-tea leaves through isolation and screening, possess strong antagonistic action to oil-tea anthracnose. In order to manufacture the biological control agent of Y13, fermented condition, wettable powder, colonization ability, garden tested were studied.(1) Optimizing fermentation condition of strain Y13Through culture condition and orthogonal tests, the optimal medium composition was obtained:glucose 2.0%, yeast extract 1.0%, beef extract 0.3%, concentration of NaCl 1.5%,30℃, initial pH6-7, the optimal fermentation condition was obtained:shake bottle fluid volume 50 mL/250 mL, inoculation volume 5%, speed 160 r/min, fermentation period 36h.(2) Development on wettable Powders of strain Y13The WP of Y13 was studied by orthogonal test, the additives'dosages of the wettable powder of Y13 were optimized:diatomaceous earth 37.17%,STPP 4.13%, SDBS 8.26%,humic acid 0.41%, original powder of Y13 50%.The quality of the formulation included water content, moisiturizing time, pH can meet national standards. Through the experiment of cute oral toxieity of biocontrol baeteria strain Y13, no one death case was observed, which showed that the strain Y13 had slight toxieity.(3) Application of bioeontrol microbial inoculum Y13The rifampin-marked strain Y13 was used to study its colonization ability in leaves and fruits of oil-tea plant. The results showed the introduced antagonistic bacteria were able to in leaves and fruits of oil-tea plant. Higher concentration＞108cfu/mL), noninterference of pathogen of oil-tea anthracnose, higher temperature (25℃～35℃), higher relative humidity (RH 95%～100%) were favorable to the colonization of the antagonistic bacteria. The microbial inoculum was tested to have good effect of preventing Camellia oleifera anthracnose (70%) in oil-tea garden, which was appropriate to the effect of Chlorothalonil as a control. |
