Research On The Water Dispersible Granules Of 30% Beta-cypermethrin And Thiamethoxam

Pesticide is an important production material in plant protection. With the increasing of the cost and period in new pesticide researching, rapid development pesticide resistance, it is becoming shortage in supplying of new kinds of pesticides. The rational combination among different pesticides play an important role in the following aspects: pest resistance controling, improving control effect, decreasing the cost, a good harvest, prolonged application longevity of pesticides and lesser environment pollution.Reference the physico-chemical properties of beta-cypermethrin and thiamethoxam. Using the interactivity testing method to design experiment and finding the synergism interval and determine the optimal ratios by using the method of co-toxicity factor and CTC, then selecting optimum additives, establishing quality detection method, conducting the field efficacy trials against Myzuspersicae on cabbage. The main research method and result are abstracted as the following:.1 The determine of beta-cypermethrin and thiamethoxam optimum ratioUsing leaf immersion to having toxicity testing on thiamethoxam and beta-cypermethrin against Myzuspersicae, the results showed that the LC₅₀ of beta-cypermethrin and thiamethoxam was respectively 76.0226±5.6237mg/L and 16.8274±1.2354mg/L.The interaction tests indicated that synergism intervals were between 38:8.5-15.2:13.6.We got the beta-cypermethrin and thiamethoxam optimum ratio which was 2:1 by using the CTC method, the co-toxicity coefficient was 196.74.2 The selection of beta-cypermethrin and thiamethoxam mixed formulationSelecting the formulation on the base of determine optimum ratio by using a lot of orthogonal experimentation. Studing on the granulating condition, then determine the best formulation as following:beta-cypermethrin 20%,thiamethoxam 10%,Dispersing agent 7%,Wetting agent B₁ 2%,Wetting agent B₂ 2%Disintegrating agent C₁2%,Binder agent D₂2%,Solid citric acid 0.01%,Bentonite (supplement to l00%)Preparing the corresponding components as previously mentioned, grinding the two kinds pesticide TC, then adding appropriate amount of water with binder agent, Fully mixing all those materials, dring the sample WG at 54±2℃until two hours,after screening we can get the 30% beta-cypermethrin ? thiamethoxam WG. The technical processing is as following:By studing the granulating conditions, we determined that the optimum water addition was 8%,the optimum particle size was 2.277μn, the optimum apertures was 1.0mm.4 The quality inspection of 30% beta-cypermethrin ? thiamethoxam WGA series quality analysis method for the 30% beta-cypermethrin ? thiamethoxam WG was established. The results indicated that the linear relationship between beta-cypermethrin and thiamethoxam was quite well. The standard deviation of beta-cypermethrin and thiamethoxam in amounted to 0.0790 and 0.0423, the range coefficient precision reached 0.394 and 0.422, and the beta-cypermethrin and thiamethoxam content in lab trials were 20.005% and 10.031%, respectively.By using CIPAC, GB recommended method, determined the indicators such as suspensibility,wettability,disintegrative etc, the result showed that the average suspension rate of the sample WG was more than 90%,the Wetting time was less than 1 min, the disintegration time less than 2 min, the Suitable pH range was between6.5-7.0.Storage stability test show that the decomposition rate of the two active ingredient was less than 5%, all the indicators of the sample WG meet the requirements. 5 Field trials of the 30% beta-cypermethrin ? thiamethoxamReferenced to the field trials criteria(GB/T17980. 11-2000), used 10% beta-cypermethrin EC and 25% thiamethoxam WG as the control insecticides.The filed trails result showed that 30% beta-cypermethrin ? thiamethoxam WG against Myzuspersicae in the cabbage had a better control effectiveness at 35mg/kg-40mg/kg. The average congtrol effect was lager than 90% affter using the sample WDG from 3-7th day.Each concentration had a good rapidly and durable effect and can effectively control the Myzuspersicae population development in the fields. The final concentration recommended for field using was 35-40mg/kg.