Abstract: Biological pesticide has broad prospects for development. Euphorbia esula Linn., as a Chinese herbal medicine, has wide distribution and rich resources, and its own toxicity can be used to develope biological pesticides. By heating 75% ethanol to extract the active ingredients in Euphorbia esula Linn., this paper carried out insecticidal antibacterial biological activity test to provide scientific basis for the development of new biological pesticide. The results showed that the extracts had good toxicity to Drosophila melanogaster and Myzus persicae. The LC50 of the extract was 75.51 mg/mL, and the Drosophila mortality was positively correlated with the concentration of the extract. The toxicity of LC50 was 9.35 mg/mL, and the corrected mortality was 85.59% when the concentration of extract was 50 mg/mL. The extracts had certain inhibitory effect on Escherichia coli, Staphylococcus aureus and Bacillus subtilis, which had a stronger inhibitory effect on Bacillus subtilis and the maximum diameter of inhibition zone was 1.53 cm. The extract of 25 mg/mL had obvious inhibitory effect on the colonies of corn leaf spot in potato dextrose agar(PDA）flat plate. The inhibitory rate was 45.28%, and the control effect of potted maize seedlings was 36.63%.

Key words: Euphorbia esula Linn., extract, antibacterial activity, biological pesticide, corn leaf spot

摘要： 生物农药开发前景广阔，乳浆大戟作为一种中草药，分布广、资源丰富，可利用其自身的毒性开发生物农药。以75%乙醇加热萃取法提取乳浆大戟中的活性成分，进行了杀虫抑菌生物活性试验，为乳浆大戟开发为新型生物农药提供科学依据。试验结果表明：提取物对果蝇及桃蚜具有良好的毒杀活性，提取物对果蝇的半致死量LC50为75.51 mg/mL，果蝇死亡率与提取物浓度呈正相关，对桃蚜毒性的半致死量LC50为9.35 mg/mL，当提取物浓度为50 mg/mL时对桃蚜的校正死亡率为85.59%；提取物对大肠杆菌、金黄色葡萄球菌以及枯草芽孢杆菌均有一定的抑菌作用，其中对枯草芽孢杆菌抑制作用较强，最大抑菌圈直径为1.53 cm；25 mg/mL的提取物对玉米大斑病菌落扩展有明显抑制作用，抑菌率45.28%，对盆栽玉米苗大斑病的防治效果为36.63%。

关键词: 乳浆大戟, 提取物, 抑菌活性, 生物农药, 玉米大斑病