The Study On Residue Behavior Of Emamectin Benzoate In CorydalisyanhusuoW.T.Wang. And Soil

Traditional Chinese medicinal materials is one of the huge treasures of the Chinese nation, as one of "Zhejiang eight famous kinds herbal medicines", CorydalisyanhusuoW.T.Wang has the function of promoting blood circulation of Qi and relieving pain, which has been applied foreground and shown a large market potential. With the increasing demand of Chinese medicinal materials, its cultivation is also growing. However, CorydalisyanhusuoW.T.Wang are often infectd by weevil in the process of planting that resulting in decline in quality and yield, which will finally affect the sales price and volume. A common used pesticide emamectin benzoate was selected as research pesticide in this paper to establish residue analytical methods and investigate the dissipation characteristics of this pesticide in Corydalisyanhusuo W.T.Wang and soil, especially in pan’an country, Zhejiang province and dongxiang country, Jiangxi province. Besides, the influence of organic matter content, pH, water content, temperature and microbial conditions on the degradation of the pesticide within the indoor environment were examined. The main results were summarized as follows:(1) The degradation of emamectin benzoate in CorydalisyanhusuoW.T.Wang and soil were fitted to the first-order kinetic equation. The half-lives of emamectin benzoate in leaves were 2.12 d(Zhejiang),2.41 d (Jiangxi) and in soil were 1.63 d(Zhejiang),2.03 d(Jiangxi) respectively. The CorydalisyanhusuoW.T.Wang was sprayed 3 and 4 times with emamectin benzoate 2.3% EC, the final residues of emamectin benzoate in CorydalisyanhusuoW.T.Wang were ND in both Zhejiang and Jiangxi. The result showed that degradation rate of emamectin benzoate was fast in field environment.(2) In indoor environment, the degradation of emamectin benzoate in soil under different conditions, such as soil organic matter content, pH, temperature and microbial conditions, were all fitted to the first-order model. Under different temperature condition, the half-lives of emamectin benzoate in soil were 9.75 d (10℃),9.00d (20℃),5.76d (30℃) of Zhejiang and 12.09 d (10℃),11.09 d (20℃),8.51 d (30℃) of Jiangxi; Under different microbial condition, the half-lives of emamectin benzoate in soil were 9.00 d (Non-sterile),14.74 d(Sterilized) of Zhejiang and 11.09 d (Non-sterile),15.03 d(Sterilized) of Jiangxi. According to the results of variance analysis in 95% confidence intervals by DPS, degradation of emamectin benzoate under different temperature and microbial conditions had significant differences, degradation of emamectin benzoate was accelerated in soil with high soil organic matter content, optimal temperature and rich microorganisms.(3) In indoor environment, the degradation of emamectin benzoate in fresh tubers and dry tubers under different temperature condition were all fitted to the first-order model. The half-lives of emamectin benzoate in fresh tubers were 20.93 d(10℃), 15.71 d(20℃),15.20 d(30℃) of Zhejiang and 22.50 d(10℃),18.04 d(20℃),15.57 d(30℃) of Jiangxi; The half-lives of emamectin benzoate in dry tubers were 32.84 d(10℃),29.36 d (20℃),26.45 d (30℃) of Zhejiang and 30.52 d (10℃),26.25 d (20℃),23.26 d (30℃) of Jiangxi. According to the results of variance analysis in 95% confidence intervals by DPS, the degradation of emamectin benzoate was accelerated in high temperature and high moisture content.