关键词: 乳浆大戟, 提取物, 抑菌活性, 生物农药, 玉米大斑病

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