| Ivermectin is a derivative of avermectin and has the advantage of broad-spectrum, high efficiency as well as environmental safety. The main mechanism of ivermectin action is that ivermectin can bind the target insect cells at specific and highly affinity sites, which leads to cell membrane higher permeability to chloride ions, and causes nerve cells or muscle cell hyperpolarization, thereby inhibits insect body into paralysis even death. At present, more and more ivermectin is used to control parasite of animals, while relatively few applications in agricultural field. Therefore, the development and application of ivermectin as a pesticide has broad prospects. This paper focuses on the ivermectin formulation with other general pesticide as subsidiaries, screening the best compatibility and the optimum ratio, and further processed into pesticide emulsion in water, which would improve the efficiency, reduce the use of single-dose, slow resistance, extend the application time, and reduce production costs of the acricides. Our research can provide scientific theoretical basis and technical guidance for the application of ivermectin in the agricultural field. Therefore, this paper focuses on the following aspects of ivermectin and avermectin, cyflumetofen. The main research methods and results are as follows:1. The toxicities of ivermectin, avermectin and cyflumetofen to Tetranychus cinnabarimis female adults were assayed respectively using the method of residual contact vial. And the result showed that the LC50 value of T. cinnabarinus to three pesticides were 7.88 mg·L-1,3.76 mg·L-1 and 28.74 mg·L-1 respectively.2. Co-toxicity factor was used to evaluate the formulation synergism and co-toxicity coefficient method was adapted to screen the optimum ratio of pesticides, thus mathematical model equation was fitted using optimum ratio and co-toxicity coefficient. The results showed that the formulation of ivermectin to avermectin and ivermectin to cyflumetofen both expressed as synergistic or additive effects. In detail, which showed synergism when the ratio of ivermectin to avermectin are 1:2.2,1:1.67 and 1:1.28, especially 1:1.28, the CTC value is 226.02. SPSS fitting mathematical model is Y=-2.8493X2+179.62X-2626.8, with theoretical optimum efficiency ratio of 1: 1.22, and the co-toxicity coefficient of 204.01. Which showed synergism when the ratio of ivermectin to cyflumetofen are 1:4,1:2,3:7 and 1:1, especially 1:1, the CTC value is 265.66, SPSS fitting mathematical model Y=-1.3787X2+79.264X-881.41, with the best theoretical efficiency ratio of 1:1 and CTC value of 257.77. From the result, synergetic ratio range of ivermectin to avermectin is narrow. In comparison, synergetic ratio range of ivermectin to cyflumetofen is larger, and co-toxicity factors are greater, which results in high consistence of optimum ratio in reality and theory.3. According to the specific proportion of ivermectin and cyflumetofen and their physical and chemical properties, emulsion in water was formulated. Research was made on the preparation of 5% ivermectin cyflumetofen emulsion in water, and the satisfactory formulation as follows:4. According to the characteristics and the basic standards of emulsion in water, the quality control indexes of the product was developed as follows:5. The control effect experiment of 5% ivermectin cyflumetofen emulsion in water was conducted in laboratory using potted plant. The results showed that 5% ivermectin cyflumetofen EW in concentration range of 8.33～12.5 mg·ai/L had a nearly effect on T. cinnabarinus compared to the control pesticide of 0.5% ivermectin EC in 8.33 mg·ai/L, and had a higher efficiency than 20% Cyflumetofen SC with concentration of 50 mg·ai/L after lth,3th,5th,7th,10th,14th days. In summary,5% ivermectin-cyflumetofen emulsion in water has good control effect on carmine spider mite, which also provided recommended concentration for the field efficacy trials, furthermore, the emulsion in water are friendly to the environment and broading application prospects. |
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