Research on the differences of the migration in soil and photolysis of different wall materials of microcapsule suspensions of beta-cypermethrin

10% microcapsule suspensions (CS) of beta-cypermethrin were prepared by using urea-formaldehyde resin,melamine-formaldehyde resin,polyurethane and polyurea as wall materials.The migration in soil and the photolysis of beta-cypermethrin in various of microcapsule suspensions were measured by HPLC with soil thin layer chromatography and UV-photolysis methods respectively.The results showed that,using the same particle-size of CS and water as developing solvent,the migration rate of beta-cypermethrin CS were ranked as polyurea,polyurethane,melamine-formaldehyde resin,urea-formaldehyde resin;the rate of the same wall material of the CS was increased along with the increasing of particle-size.Under UV light,the photolysis rate were ranked as beta-cypermethrin technical,EC,microcapsule suspensions which were polyurea,polyurethane,melamine-formaldehyde resin and urea-formaldehyde resin used as the wall materials,and their half-lives were 2.3,9.4,20.7,39.0,45.8 and 51.9 h,respectively.Their half-lives were followed by 5.8,5.9,6.9,6.7,12.9 and 17.3 d under the natural light.The photodegradation rate of CS was significantly lower than technical and EC,so its efficiency period would be extended.