贝莱斯芽孢杆菌对黄瓜白粉病的毒力与防效及对黄瓜的安全性评价

为探讨微生物杀菌剂贝莱斯芽孢杆菌对黄瓜白粉病的防治作用。试验采用5个黄瓜品种：‘中农26’、‘金胚98’、‘长春密刺’、‘津玉168’、‘雪白黄瓜’。采用盆栽法测定贝莱斯芽孢杆菌对‘中农26’黄瓜白粉病菌的室内毒力，通过田间药效试验在山东、四川分别测定贝莱斯芽孢杆菌对‘津玉168’、‘雪白黄瓜’黄瓜白粉病的防治效果，并采用盆栽法测定贝莱斯芽孢杆菌对‘中农26’、‘金胚98’、‘长春密刺’黄瓜植株的安全性。贝莱斯芽孢杆菌对‘中农26’黄瓜白粉病菌的EC₅₀值为0.267亿孢子/mL，室内活性较强；山东、四川两地贝莱斯芽孢杆菌防治‘津玉168’、‘雪白黄瓜’黄瓜白粉病2次药后14 d防效为62.08%～75.58%，与对照药剂相比防效更好；200亿孢子/g贝莱斯芽孢杆菌可溶粒剂3000、6000、12000 g a.i./hm²对‘中农26’、‘金胚98’、‘长春密刺’黄瓜生长抑制率均无显著性差异，安全。贝莱斯芽孢杆菌对黄瓜白粉病有较好的室内活性与田间防治效果，对黄瓜植株相对安全，可以推广使用。

Bacillus velezensis: Toxicity and Field Efficacy Against Cucumber Powdery Mildew and Its Safety Evaluation

The study aims to explore the control effect of microbial fungicide Bacillus velezensis on cucumber powdery mildew in field. Five cucumber varieties were used in the experiment including ‘Zhongnong 26’, ‘Jinpei 98’, ‘Changchunmici’, ‘Jinyu 168’ and ‘Xuebaihuanggua’. The toxicity of Bacillus velezensis against Sphaerotheca fuliginea of ‘Zhongnong 26’ was determined by pot method in the laboratory, the control efficacy on ‘Jinyu 168’ and ‘Xuebaihuanggua’ were investigated in Shangdong and Sichuan, and the safety evaluation on ‘Zhongnong 26’, ‘Jinpei 98’ and ‘Changchunmici’ were conducted by pot method. Under indoor condition, the EC₅₀ value of Bacillus velezensis on ‘Zhongnong 26’ was 26.7 million CFU/mL, and the activity was relative high. The control efficacy of Bacillus velezensis in Shangdong and Sichuan was 62.08%-75.58% 14 d after two times of application, which was significantly better than that of control pesticides. The growth inhibition rate of ‘Zhongnong 26’, ‘Jinpei 98’ and ‘Changchunmici’ had no significant difference when the varieties were sprayed 20 billion CFU/g Bacillus velezensis SG at the dosage of 3000, 6000 and 12000 g a.i./hm², indicating the safety of the fungicide. Bacillus velezensis has good indoor activity and control efficacy against cucumber powdery mildew, and it is safe for cucumber and can be promoted for application.