[Objective] This study aimed to investigate the combined control effects of endophytic bacteria at different growth stages against cotton Verticfllium wilt and pro- vide a new strategy for the biocontrol of other soil-borne diseases. [Method] Endophytic bacteria with high resistance against Verticillium wilt were isolated from seedling, squaring and boll-setting cotton vascular, respectively. Their 16S rDNA se- quences were detected for comparative analysis. Three biocontrol strains were se- lected and identified, whose colonization roles in cotton plants were explored. The control efficiency was determined with indoor and field experiments. [Result] Accord- ing to the 16S rDNA sequence homology, the three strains were identified as Paeni- bacillus polyrnyxa YUPP-8, Paenibacillus xylanilyticus YUPP-1 and Bacillus subtilis YUPP-2, respectively. Results of colonization assessment showed that three strains all could be successfully colonized in cotton vascular. However, application amount had a positive effect on the number of colonized biocontrol bacteria in cotton, strain YUPP-8 had the largest number of colonized biocontrol bacteria in seedling period, strain YUPP-1 had the largest number of colonized biocontrol bacteria in squaring period, and strain YUPP-2 had the largest number of colonized biocontrol bacteria in boll-setting period. Indoor pot experiment showed that cotton plants in combined bio- control bacteria treatment group were not infected in flowing period, while Verticillium wilt morbidity rate of cotton treated with single strain in seedling period were 6.7% （YUPP-8）, 6.7% （YUPP-1） and 13.3% （YUPP-2）; however, Verticillium wilt morbidity rate wilt of the control reached 80%. Field experiment conducted during 2010-2011 showed that the combined application of three strains had better effect than separate application; specifically, Verticillium wilt morbidity rate and disease index of cotton in boll-setting period with combined application of three strains in 2010 were 9.4% and 6.5, respect
茄子黄萎病是严重影响茄子产量的土传病害。为了有效控制该病害,从开花期茄子根茎中分离得到对黄萎病菌具有强烈抑制作用的内生生防菌株QZ-8,其抑菌直径达24 mm,经16 S rDNA序列分析确定其为枯草芽孢杆菌。室内定殖试验表明,QZ-8菌株能顺利定殖于茄子根际和维管束中,最高定殖量可达1×105CFU/g茄组织。另外QZ-8菌株可促进茄种子的萌发、茄子幼苗及根系生长。室内盆栽试验表明,QZ-8对茄子黄萎病均具有很高的防效,可达78.98%,持效期较长。
