Study On Degradation Dynamics Of Imidacloprid In Tea And Soil

As a drink, tea enjoys a good popularity all around the world for its rich in caffeine, proteins, amino acids, vitamins and so on. And it is well known that tea leaves are processed directly after picked up without any clean and disinfecting procedures. So pesticide residue on tea became a focus which has been drawn much attention to in recent years.Chongqing is one of the important tea bases of China for the climate there is good for tea plant growing. However, tea disease and insect happenes frequently during the growing period. And at present, chemical pesticides are main control measures in Chongqing tea garden, which are incident to residue. Thus, an investigation of pesticide residue was made in the large-scale tea garden in Chongqing, imidacloprid dynamic in tea, soil and tea process was studied to provide valuable reference for government and tea enterprises. The main results are as follows.1 Control of pest and pesticide residue situation in Chongqing tea gardenThrough the investigations of Wansheng-Genggu and Banan-Ersheng tea garden and the plant protection station in Chongqing, the results indicated that insect pests were prominent, with tea greenery cicada, tea mite and tea leaf roller as main harmful insects, which happened heavily in the summer and fall tea. Imidacloprid and cypermethrin are used widespread and the sprayed dose are often higher than recommendation dose.According to code GB/T 5009. 146-2003 《Planted Food Organic Chlorine And Synthetic Pyrethroids Pesticide Multiresidue Determinations Methods 》 .cypermethrin, fenvalerate, fenpropathrin BHC and DDT were monitored in the Chongqing large-scale tea enterprise. Only cypermethrin was detected in the fall tea of Rongchang-Tianganyuye and both summer and fall tea of Wansheng-Genggu, and content is 0.006 ~ 0.008 mg/kg, which is lower than the limits by far.2 Analytical method of imidacloprid residue in tea and soil...