The Study On The Screening, Formulation And Controlling Of Acaricide Against Panoneychus Citri

Panoneychus citri is one of the most important pests to citri,which seriously damage growth status,quality and output of citri.Therfore controlling the damaging of Panoneychus citri has very important senses.This paper have studied on screening, formulation in lab and control in field of acaricide against Panoneychus citri.1.Pesticides of screening:Primarily screening was held with nine insecticides against the Panoneychus citri by double gluing.The results indicated that emamectin, imidacloprid,beta-cypermethrin,fenpropathrin,fenbutatin oxide,pyridaben,matrine had better effects than other insecticides and entered the re-screening between two insecticides.The proportions of beta-cypermethrin to methylamino abamectin(1:1) showed best toxicity,which of LC50 and CTC were 1.2079μg/mL and 336.34 respectively.2.Pesticides formulation:According to the physical and chemical characters of beta-cypermethrin and methylamino abamectin,the microemulsion of 2.5% beta-cypermethrin and methylamino abamectin was sure to formulate.So held the selection experiment on cosolvents,surfactants and water quality respectively.The result indicated that methanol to ethyl acetate(6:1)with 6～10%quantity and emulsifier SQ-6 or 305 with 6～10%quantity got stabile and good characters and chose drink water as formulating water.So got two formulation WXG-1 and WXG-2. The detection results indicated that the formulations was clear and well emulsification characters.The average decomposition ratio were only 3.25%and 2.24%respectively after heating.Also qualified after cooling and the bio-assay results expressed very well efficacy and the Lc₅₀were 3.2575μg/mL and 2.7721μg/mL respectively.So held the field trial to check the efficacy.3.The field trial of the two formulation:2.56%WXG-1 and 2.52 WXG-2 were carried out field trial in April and September,2006 with 73%propargite EC, 10%pyridabenEC,20%fenpropathrin EC,15%pyridaben,4.5%beta-cypermethrin and 5%methylamino abamectin as controls.The results indicated that the efficacy of WXG-1 and WXG-2 almost reached 70%after spraying 3 days,a litter lower than those of 4.5%beta-cypermethrin and 5%methylamino abamectin.However,the difference was insignificant.After spraying 10 days,the efficacys of all treatments almost reached 90%and showed very good quick efficacy,what's more,there were not significant between the treatments.After spraying 20d,the efficacys of all treatments reduce some levels,but those of 1500 times and 2000 times of WXG-1 and WXG-2 still remained almost 70%without damaging to citri during the experiment.So WXG-1 and WXG-2 could be practiced in the controlling Panoneychus citri with 1500 times to 2000 times.