Study On The Insecticidal And Bacteriostatic Active Of Angelica Dahurica Ect. Three Kinds Of Plants

This selection selected Angelica dahurica, Veratrum dahuricum Loes.f and Ambrosia artemisiifolia L. for the raw material,study the control effect and security of their crude extracts to Hyphantria cunea and Cytospora chrysosperma (Pers.) Fr. Which are more common and have serious harm on the forestry.Using soxhlet extraction and ultrasonic extraction methods, extract the insecticidal and antibacterial active compounds of test plants, these two methods are simple and effective, and it is easy in application of mass production.Through Toxicity test of Hyphantria cunea, the insecticidal effect of 3rd instar larvae of Hyphantria cunea is:angelicadavurica>ragweed> veratrum dahuricum lcesener. Efficacy changes over time through Indoor observation,which is inversely proportional to time and proportional to the concentration. The death of test insect reached the peak after the second day of pesticide application, then it presented a downward trend. The lethal concentration LC50 of angelicadavurica crude extracts to Hyphantria cunea is 4599.30μg/mL (concentration), the lethal concentration LC50 of ragweed crude extracts to Hyphantria cunea is 6069.34μg/mL (concentration), the lethal concentration LC50 of veratrum dahuricum lcesener crude extracts to Hyphantria cunea is 9644.71μg/mL (concentration).The inhibition test on pathogen of cytospora chrysosperma shows that, the inhibition of 6 kinds of concentrations of crude extracts of angelicadavurica to the pathogen of cytospora chrysosperma was stronger than ragweed,the effect is better and more stable. The effect of crude extracts of these two plants was the best when its concentration is 80 mg/mL,the bacteriostasis of lmg/mL crude extracts showed little change over time,the inhibitory effect is more stable. The inhibiting concentration EC50 of angelicadavurica crude extracts to the pathogen of cytospora chrysosperma is 0.11μg/mL (concentration), the inhibiting concentration EC50 of ragweed crude extracts to the pathogen of cytospora chrysosperma is 968.84μg/mL (concentration).Through the acute toxicity test, the mice median lethal dose of angelicadavurica is micro-toxic, the mice median lethal dose of ragweed is micro-toxic, the mice median lethal dose of veratrum dahuricum lcesener is micro-toxic, it is harmless to ecological environment and mammals,and it can be developed as botanical pesticide.