Study Of Insecticidal Activity Of Rubia Cordifolia L. Against Helicoverpa Armigera

Rubia cordifolia L. belongs to Rubia. It has obviously pharmacological actions such as hemostasis, promoting blood circulation to remove stasis, relieving cough and reducing sputum. Studies have shown that Rubia cordifolia L. contains anthraquinone, glycosides, naphthoquinone, terpene, peptides, polysaccharides and other ingredients. At present, the biological activity of Rubia cordifolia L. on the agricultural pest has few documents. The biological activity of Rubia cordifolia L. on H.armigera and the separate was researched in this ariticul.1. The bioactivity of the 6 kinds of plants powder against H. armigera was tested by diet-incorporated method. The Rubia cordifolia L. showed the best effect of growth inhibition and the inhibitory rate of weight was reached 89.3% on the 5th day. The larval duration of Rubia cordifolia L. was extended 12.6 days compared to the control and the pupa weight, pupating rate and hatching rate were significantly lower. Glycyrrhiza was 42.9% on the 5th day and fructus quisqualis was 47.8% on the 3rd day, respectively. But the pupa weight, pupating rate and hatching rate had no significant influence.2. The growth and development effect of the powder of Rubia cordifolia L. on the life history of H. armigera were tested by diet-incorporated method. The results showed that the powder of Rubia cordifolia L. had the strong inhibition of growth on the H. armigera. On the 5th day, the inhibitory rate of weight was reached 92.4%. The H. armigera all died in the lavare stage if the treatment diet of Rubia cordifolia L. powders did not renew with the normal diet on the 5th day. The average number of eggs deposited by a single female was 1019 and the maximum numberof the eggs deposited by a single female was 1503. The fecundity was significantly reduced.3. Eight different solvents were used to extract substances from Rubia cordifolia L. The results showed that the extracts of ethanol ether, ethyl acetate, petroleum ether and acetone had strong inhibition of growth on the H.armigera. The 95% ethanol extract showed the best effect of growth inhibition and the inhibitory rate of weight was reached 82.2% on the 5th day. The bioactivities of eight solvents above were studied. The results showed that the 95% ethanol had highest antifeedant effect on the larvae of H. armigera, its antifeedant rate after 48h was 99.3%.But the contact toxicity of eight extract against H. armigera were not significantly.4. The 95% ethanol extracts of Rubia cordifolia L. was fractioned by liquid-liquid partion method with petroleum ether, chloroform, ethyl acetate and butanol.The results showed that the ethyl acetate extracts had stronger biological activity than others, On the 5th day, the inhibitory rate of weight was reached 85.5%. The pupatingrate and emergence rate were lower than control.The chloroform extracts was separated by using the method of Silica gelcolumn chromatography. The result shows that the 4 components had the strongest inhibition of growth. On the 5th day after the treatment, the inhibitory rate of weight was reached 93.6%. The pupating rate and emergence were lower than control.5. The 4 components was separated by using the method of Silica gelcolumn chromatography and got the crystallization.