Preparation Of The Biological Pesticide From Tung Seed Meal And The Investigation Of Its Insecticidal Activity

In this article, we have performed the extraction of Tung seed meal and calculated the efficiency. The pesticidal activity was examined. The component of Tung seed meal extract was analyzed. We have prepared two kind of pesticide, EC and EW, from Tung seed meal extract and assessed their pesticidal activity. A series of experimental results indicate that Tung seed meal is promising to be developed into botanical pesticide product. The specific results are as followed:We have performed 95% ethanol heat reflux on Tung seed meal, of which the extraction rate is 9.86%. After using petroleum ether oil removal, we performed the chloroform and ethyl acetate extraction for the extract. The extraction rate for chloroform and ethyl acetate is 0.57% and 0.12% respectively. We have examined the pesticidal activity for two extract. The chloroform extract was remarkably efficient to kill armyworm, small armyworm, litura, spotted spider mite and aphid. In comparison, ethyl acetate extract did not reach the criteria as the pesticide for all of these pests. Therefore, we have chosen the chloroform extract of Tung seed meal for the later experiment.We used AB-8 macroporous resin to crudely separate the chloroform extract, and thin layer chromotography to combine the samples. We have used LC-10A HPLC to collect and analyze the characteristic peaks. We have used LTQ velos Pro LC-MS to analyze the component of the extract, as well as the NMR. Based on that, we proposed that the major component should be (Z)-8-acetyl-2-ethyl-6-ethylidene-3-methyl-5-vinyl-3,4,6,7,8,8a-hexahydronaphthalen-1 (2H)-one.Taking the chloroform extract as the original drug, we have prepared the EC and EW. The EC recipe is chloroform extract (60%), ahydrous ethanol (20%), Tween-60 (5%) and Cremophor (15%). The killing assay indicated that it was less efficient for armyworm, cabbage caterpillar, spotted spider mite or diamondback moth. However it was efficient for bean aphid, of which the LC50 was 7.76mg/L. The EW recipe is chloroform extract (40%), Cremophor (8%), lignin sodium sulfur (1.5%), distilled water (50.5%). The killing assay indicated that its LC50 to bean aphid was 2.92mg/L. The mechanism study suggested that EW reagent had tag, stomach and food refusal activity.We have conducted investigation on the pesticidal efficiency in potted and field experiment.For the potted experiment, treatment of 40,20 and 10mg/L had prevention effect for bean aphid. Killing efficiency post 7 days were 100%,96.87% and 91.91%. For the field experiment, EW reagent (30,15g ai/ha) treatment prevented cabbage aphid effectively. The killing efficiency post 7 days were 95.59% and 83.44% respectively.