杧果炭疽菌拮抗细菌的筛选鉴定及其防病效果

为寻找对杧果炭疽菌Colletotrichum gloeosporioides有效的生防菌株，从瓜叶白粉病病斑上分离得到104株细菌，通过平板对峙培养筛选出16株拮抗细菌，分别测定其在8种不同培养基中的抑菌活性，筛选出有较强抑菌作用的9A、26A和4N菌株进行室内、果园防病试验，并对具有较好防治作用的9A、26A菌株进行了鉴定。结果显示，拮抗菌9A、26A和4N分别在南瓜汁、红薯汁和马铃薯汁培养基上的抑菌活性最高，对杧果炭疽菌菌丝生长抑制率分别为88.83%、87.83%和85.87%；室内9A、26A和4N菌株菌液处理离体果实，24 h后接种炭疽菌分生孢子液，对杧果炭疽病的防治效果均达100%，与咪鲜胺对照组相同；在果园9A和26A的防病效果分别为98.4%和90.5%，显著高于对照组的防效78.8%，而4N的防效只有58.2%。根据形态、生理生化特征及16S rDNA 序列分析结果，将菌株9A和26A鉴定为枯草芽胞杆菌Bacillus subtilis。研究表明，菌株9A和26A具有较好的生防利用价值。

Screening, identification and control efficacy of antagonistic bacteria against Colletotrichum gloeosporioides on mango

In order to seek more effective antagonistic bacteria, 104 bacterial strains were isolated from the spots of powdery mildew on the leaves of cucurbit, 16 strains of antagonistic bacteria were screened out by confrontation PDA plates and their antifungal activities were tested in eight different culture media. The strains 9A, 26A and 4N with better antifungal activity were selected for disease control test, and 9A, 26A strains with better control efficacy were identified. The results showed that 9A, 26A and 4N strains cultured respectively in pumpkin, sweet potato and potato media had the best antifungal activity, with the inhibition rates of 88.83%, 87.83% and 85.87%, respectively, against mycelial growth of C.gloeosporioides. Detached mango fruits were treated with the suspension of 9A, 26A and 4N at 24 h before inoculation of the suspension C.gloeosporioides, and the control efficacy were both 100%, with the same result from the treatment with prochloraz (EW). The control efficacies of 9A and 26A were 98.4% and 90.5%, respectively, on fruits in field, which were significantly higher than those of the treatment with prochloraz (EW), but the control efficacy of 4N treatment was 58.2%. The strains of 9A and 26A were identified as Bacillus subtilis based on morphological, physiological and biochemical characteristics and phylogenetic analysis of 16S rDNA sequences. The results indicated that 9A and 26A strains have better bio-control value.