Preparation Of Microcapsule Of Fenvalerate-malathion Mixture And Its Application In Control Of Carposina Niponensis Walsingham

The emulsifiable concentrates of fenvalerate-malathion mixture is a high effect preparation in control of Carposina niponensis Walsingham and Conopomorpha sinensis Bradley happened on fruit trees and has been in commercial for twenty years. But its period of persistent control is relatively short. In this paper we encapsulated fenvalerate and malathion in a microcapsule. The wall material was used of gelatin and sodium alginate, which is environment-friend material and no harm to human and animal. In lab and field the comparison tests against C. niponensis Walsingham were carried with microcapsule and emulsifiable concentrates of fenvalerate-malathion mixture.The main results were summarized as follows:1. By screen of wall materials of ratio and content, core solvent and dispersant, the final optimal receipt of microcapsule preparation is(w/w): 5% of fenvalerate, 15% of malathion, 15% of mixture solvent by xylene and thlorobenzene at ration of 4:1, 1.25% of gelatin, 1.25% of sodium alginate, 1.5% of dispersant NNO, 0.2% of xanthic acid gum, 4.5% of ethylene glycol and deionized water to 100%.2. The characteristics of microcapsule of fenvalerate-malathion mixture were tested used microscope observation, particle diameter analysis, encapsulation rate determination. The diameter of microcapsule was minute, had regular morphology of circle and had good dispensed.3. Under optimal condition, the mean diameter of microcapsule was 7.07, the loading ratio was 37.36%, and the encapsulation ratio could reach 88.89%. The suspension rate was higher than 85%. The decomposition rate of the active ingredient was under 2% and water separate rate was under 2%. All the specification could reach the standard of suspension concentrates.4.The results of lab and field test against C. niponensis Walsingham indicated that the control period of microcapsule suspension of fenvalerate-malathion mixture was prolonged more than emulsifiable concentrates. At the same dilution folds, 20% microcapsule suspension had the equal effect with that of 30% emulsifiable concentrates.