枯草芽胞杆菌NJ-18对油菜菌核病的防治效果及其定殖动态

Biological control of rapeseed sclerotinia stem rot caused by Sclerotinia sclerotiorum with Bacillus subtilis NJ-18 and its colonization dynamics on the plant

菌株NJ-18是从油菜田土壤中分离筛选到的一株具有抗真菌活性的枯草芽胞杆菌。试验结果表明菌株NJ-18与油菜菌核病菌对峙培养能形成3.4 cm的抑菌圈;能抑制油菜菌核病菌菌丝生长发育;强烈影响菌丝生长量,NJ-18发酵滤液稀释62.5倍时对菌丝生长量抑制率高达96.7%,稀释1 000倍时抑制率16.7%。油菜离体叶片试验表明,NJ-18发酵液原液对菌核病的防治效果高达100%,原液稀释200倍后防效10%。大田试验结果表明,NJ-18发酵液稀释500倍对油菜菌核病的防治效果高达57.4%,明显高于用量为150 g a.i./hm2的醚菌酯48.1%的防治效果。采用浸根法研究NJ-18在油菜上的定殖动态表明,菌株NJ-18能够在油菜体内定殖,并能从油菜的根部向叶子扩散。

Bacillus subtilis strain NJ-18 was isolated from the soil of oilseed rape field and showed antagonistic ability against Sclerotinia sclerotiorum. The antifungal assay showed that the inhibition zone of strain NJ-18 reached 3.4 cm by dual culture method against S. sclerotiorum and affected the growth and development of the fungai mycelium. 62.5 times and 1 000 times diluted cell free filtrates of strain NJ-18 inhibited 96.7% and 16. 7% growth of S. sclerotiorum mycelium , respectively. The control efficacy of the pure fermentation and its 200 time dilution inhibited the disease on the detached leaves inoculated with S, sclerotiorum by 100% and 10% respectively. In field trail, the control efficacy of 500 times dilution of the fermentation against rapeseed sclero- tinia stem rot reached 57.4%, which was higher than 48. 1% of Kresoxim-methyl efficacy at 150 g a. i./hm2 treatment. The results of investigation showed that bacterial strain NJ-18 could colonize in the plant of oilseed rape and transfer to the leaves from soil treatment.