Aphid Alarm Pheromone Micro-emulsion

(E)- β-Farnesene is one of aphid alarm pheromones with potential worth for scientific research and practical application. Based on the property to drive aphid away, (E)- β- Farnesene could keep aphid out of greenhouse or agricultural sheds. If (E)- β- Farnesene is used with some general insecticides together, aphid could be killed directly and on its own initiative, which is good for environment protection, foodstuff safety, etc. Most of the raw pesticides must be formulated for the use in agriculture. Selection of pesticide formulation is the key to effectiveness of pesticide, In most case, the environmental pollution caused by pesticide is from its assistant agents. So the appropriate selection of pesticide formulation is good either for effectiveness of pesticide, or for reduction of the pollution caused by pesticide to the biological environment. To solve this problem, the microemulsion of aphid alarm pheromone, a new formulation that reduce the content of organic solvents, was studied.Microemulsions are stable, isotropic, transparent or semitransparent mixtures of oil, water and surfactant, frequently in combination with a cosurfactant. Droplets of microemulsion are spheres or adopting the shape of a prolate ellipsoid which have characteristic dimensions of 10-100 nm.In this study, according to the theories of microemulsion, the formulation of aphid alarm pheromone microemulsion (O/W) was researched and optimum emulsifier and co-emulsifier were selected by using the preduoternary phase diagram. The optimum emulsifier was the mixture of 2201 and Tween80 (3 : 1, m /m ), which was 17.65% weight of total composition; the co-emulsifier was n-butanol , by 13.24% weight, and the other component was water. And the GC method was set up to determine the concentration of EBF in microemulsion .According to the related universal standard of pesticide microemulsion, the quality indexes for the preparation of aphid alarm pheromone microemulsion were established. It comprised appearance, content of farnesene, pH value of the microemulsion, cold stability, heat stability and dilute stability and temperature range of transparence. The indexes of 2.94% aphid alarm pheromone microemulsion were as follows. The composition should appear as a single phase without any particulate or colloidal material or a second phase being present when viewed by thenaked eye. The dispersion should remain clear and free of precipitation or flotage at the temperature range of 0-48℃ .The freeze-thaw test indicated that the frozen formulation could recover independently at the room temperature. After heat storage at the temperature of 54℃,the decomposition rate of (E)- β- Farnesene should be lower than 3%. The 100 fold dilution of the aphid alarm pheromone microemulsion should be up to grade.