Preparation And Efficacy Test Of Pesticide Microemulsion

Nowadays, along with increasing awareness of environment protection as well as demand of environment protection for sustainable economy development, people must consider how to prepare green farm chemicals and apply these green preparations in agricultural production. So the development of pesticide formulation is towards environment protection, economy and saving time. Among these preparations, O/W pesticide microemulsion as a new formulation becomes focus of reseach, and has characteristics of high efficacy and little pollution. So the study of microemulsion has many important meanings in agriculture.Beta-cypermethrin and phoxim are two high efficacy and low toxicity insecticides that have different mechanisms of action. Propiconazole is an inhale triazole bactericide with action of protection. Acetochlor and quizalofop-p-ethyl are selective herbicides that can control grass weeds and broadleaf weeds, respectively. Today, EC that contains amounts of organic solventis mainly prepared. When this kind of formulation is applied in agriculture, it will give pollution to environments, and may cause medicinal harm to plants and waste to resources, and person and domestic animal may be easily poisoned if it is appplied by mistake.So Beta-cypermethrin plus phoxim ME and propiconazole ME and acetochlor plus quizalofop-p-ethyl ME were prepared in this paper, and field efficacy tests were respectively conducted. The main contents of this thesis include the following points:1. Preparation of pesticide microemulsionThe species and dosage of solvents were respectively screened according to the different physical and chemical properties in this thesis. When microemulsions were prepared, solvents were added to dissolve solid or sticky farm chemicals into flowable solution.Non-ion surfactants with HLB value were selected according to the different chemical structures in this paper. Laser size analyzer was used to measure grains of microemulsions, and the main non-ion surfactants were screened, then the dosage and proportion of non-ion surfactant plus negative-ion surfactant were respectively experimented in detail, and the qualified microemulsions were prepared.Water quality was especially researched because approximate 40%-60% water was added to microemulsions in this paper. Different water quality was respectively tested to apply microemulsions to various regions. The results showed that water quality was an important factor that influenced the physical stability, and water with no more than 342mg/L hardness could be used in microemulsions.According to different physical and chemical properties of the active ingredients, the p.H value in ME was regulated in this paper, and the decomposed ratios of these ingredients were controlled. The results showed that the acid-base value was an important factor that influenced the stability hot storage, and that the decomposed ratios of active ingredients reached no more than 5% in microemulsions.Stability test of low temperature was conducted in this paper. The tests validated that microemulsions were qualified when they were stored at low temperature. Though an amount of water was added to microemulsions, the results indicated that microemulsions could be stored at -10-0℃in cold region, and that microemulsions were not frosen, separated, crystallized, and so on.2. Field efficacy tests of pesticide microemulsionThe field trials were conducted to validate the efficacy of 15% beta-cypermethrin. plus phoxim microemulsion in control of vegetable pest, and to determine the optimum application rate. For Pieris Rapae L. and Spodoptera Litura Fabricus control, the results indicated that the best rate of this kind of ME was 1200 to 1500mL/hm~2. The control effect reached 90.0% or higher 5d after application, and the duration reached over 7 days. All treatments at the above rates caused no vegetables injury.The field efficacy of 10% propiconazole microemulsion in controlling grape powdery was consecutively conducted three times, with 20-30d interval. The results showed that this kind ofmicroemulsion at 525 to 562.5mL/hm~2 provided≥89.4% and≥88.7% on leaves and fruits in the early stage of disease, respectively. All treatments at the above rates caused no grapes injury.The test efficacy of 15% acetochlor plus quizalofop-p-ethyl microemulsion for weed control ha soybean field indicated that this kind of microemulsion provided excellent control of the main grass weeds at 1500-2100mL/hm~2 30d after application, with 95% or higher reductions ha plant number and fresh weight respectively. Good control was also provided against the broadleaf weeds, with 80.1%-82.5% reduction in fresh weight. Overall weed control was significant, with 86.1% or higher reductions in plant number and fresh weight respectively. All treatments at the above rates caused no soybean injury while crop yield was significantly improved.