Study On The Mixture Of Acetamiprid And Bifenthrin Controlling Empoasca Vitis

Empoasca vitis (Gothe) is a key pest in tea plantations in China, and it is seriously affects the yield and quality of tea production. Application of pesticide is most commonly methods for controlling the insects in the tea production. However, the repeated use of pesticides has encouraged the development of resistance to the pesticides in the target insects. Mixing pesticides which have different activities is one of the best ways to stave resistance of insects. Developing a mixture of pesticides on Empoasca vitis has an important practical significance for tea production.In this study, Empoasca vitis was as a research target. The optimal proportion of the mixture of acetamiprid and bifenthrin were selected. Preparation of the mixed variety, the mixed pesticide product standardization, and manufacture technology were research. The field efficacy trial of the mixture against target insect, the toxicity on the tested animals and the safety on the tea plants were tested. A new mixed agent for controlling Empoasca vitis was developed.The toxicity of acetamiprid and bifenthrin to mixture at different ratios on 2nd instar nymph of Empoasca vitis were determined by the bioassay. The results showed that 5 kinds of mixtures had different synergisms, of which the mixture of acetamiprid:bifenthrin=1:2 was the most significant with the co-toxicity coefficient (CTC) of 319.7764. It was identified as the optimal proportion on mixed acetamiprid and bifenthrin.Considered from the physical and chemical characteristics of acetamiprid and bifenthrin, formulation-micro-emulsion (ME) was selected for the mixed pesticide. By screening test, the formula of 4.5% acetamiprid-bifenthrin ME was as follows:acetamiprid (1.5%±0.2%), bifenthrin (3.0%±0.3%), xylene (4%), cyclohexanone (8%), propylene glycol (4%), benzene sulfonic acid calcium (2%), castor oil ethoxylates (10%) and water (fill to 100%).According to the intermediate test results and the specific requirement in ME by pesticide industry in China, the 8 key indicators of product control project, such as The content of acetamiprid and bifenthrin, pH, persistent foaming, emulsion stability, transparent temperature range, the stability in low-temperature storage and thermal storage, and their analysis were develop as a product standard. Among them, the method of quantitative analysis for acetamiprid was by high performance liquid chromatography (HPLC) with 5μm Nova-Pak C18 column for the packing and variable wavelength UV detector. the methanol was used as solvent and 55% H2O in methanol (v/v) was used as mobile phase, and the method of quantitative analysis for bifenthrin was by gas chromatography (GC) with SE-54 capillary column and FID detector, the acetone was used as solvent and triphenyl phosphate was used as internal standard. The results of the field efficacy trial of the mixture against Empoasca vitis had shown that the mixtures of 4.5% acetamiprid-bifenthrin ME in the dos of 16.875-30.375 g/hm2 had been greater than 90% on Empoasca vitis after being applied to the tea trees form 1 to 14 d. And it was the well as 2.5% bifenthrin EC in the dos of 22.5 g/hm2 (a.i) on the pest and was very significant than 3% acetamiprid EC in the dos of 30.0 g/hm2 (a.i) on the pest. The results of the field safety trial showed that the safety factor to the tea plants were over 4.The results of the toxicity of the agent on tested animals show that the acute oral LD50 were 681 mg·kg-1·BW (low toxicity level) and acute dermal LD50 were> 2000 mg·kg-1·BW (low toxicity level) to the wistar male and female rats, and the average intensity eye irritation to rabbits was 3.5 after 48 h (mild irritant level), and the acute skin irritation the highest score to the rabbits is 0 (no irritation), and the the skin metamorphosis (sensitized) intensity to the guinea pigs were I (weak sensitization level).It is suggested that 4.5% acetamiprid-bifenthrin ME is a low toxicity mixture pesticide against Empoasca vitis, and it is safe to tea plants.