Study Of Insecticidal Activity Of Polygonum Multi Florum Thunb Against Helicoverpa Armigera

Polygonum multiflorum Thunb belongs to Polygonum. It has obviously pharmacological actions such as anti-aging,enhance immunity and antibacterial. Studies have shown that P. multiflorum contains anthraquinone, stilbene glycosides, phospholipid and other ingredients. At present, the biological activity of P. multiflorum on the agricultural pest has not been reported.so,the biological activity of P. multiflorum on H. armigera and the separate was researched in this ariticul .1.The bioactivity of the 9 kinds of plants powder against H. armigera was tested by diet-incorporated method. The P. multiflorum showed the best effect of growth inhibition and the inhibitory rate of weight was reached 90% on the 5th day. Clerodendrum bungei and Cassia bark was 87.3%and 83.4% , respectively.Leptopus Chinensis and Artemisia annua Linn had the weakest inhibition of growth on the H.armigera and inhibitory rate of weight was 55.4%and 38.5%, respectively.The larval duration of P. multiflorum was extended 6 days compared to the control.2.The growth and development effect of the powder of P. multiflorum on the life history of H. armigera were tested by diet-incorporated method . The results showed that the powder of P. multiflorum had the strong inhibition of growth on the H. armigera larva. On the 5th day, the inhibitory rate of weight was reached 92.3%. The H. armigera all died in the laval stage if the treatment diet of P. multiflorum powders did not renew with the normal diet on the 5th day.The pupa weight, pupating rate and emergence rate were significantly lower.The fecundity were significantly reduced. The corrected mortality was 63.7% and 100% of the treatment diet was been renewed and the treatment diet did not renew on the 5th day, respectively.3.The water and 70% ethanol were used to extract substances from P. multiflorum. The results showed that the two extracts had strong inhibition of growth on the H.armigera, and the inhibitory rate of weight was 79.4% and 81.3% on the 7th day, respectively. The larval duration was extended 4.9 days and 5.5 days, respectively.4.The ethanol extracts of P. multiflorum was fractioned by liquid-liquid partion method with chloroform and ethyl acetate.The results showed that the ethyl acetate extracts had stronger biological activity than the chloroform extracts; On the 5th day, the inhibitory rate of weight was reached 95.6% .The pupatingrate and emergence rate were siginificantly lower than control5.The ethyl acetate extracts was separated by using the method of Silica gelcolumn chromatography. The results showed that the components of dichloromethane , the mixture of dichloromethane and ethyl acetate, ethyl acetate , the mixture of ethyl acetate and carbinol had no significant effect.6.The crude extract was separated by using the method of macroporous resin. The result showed that the extracts of 50%ethanol components had stronger inhibition of growth than the extracts of water.The inhibitory rate of weight was 76.9% on the 5th day. The pupa weight ,pupating rate and emergence rate were siginificantly lower than control.7.The extracts of 50%ethanol components was separated by using the method of silica gelcolumn chromatography. The result show that the E components had the strongest inhibition of growth. On the 5th day after the treatment, the inhibitory rate of weight was reached 80%. The pupating rate and emergence were siginificantly lower than control. The corrected mortality was 63.7%.8.The compoments of E was identificated by HPLC and the result showed that the compoments of E were not 2,3,5,4'-Tetrahydroxy-stilbene-2-O-β-D-glucoside and emodin.