25%Pymetrozine and thiamethoxam suspension residues detection and degradation in the rice ecosystem

In this work,we developed a novel method of simultaneous determination of residues and dynamics degradation for both pymetrozine and thiamethoxam in soil,rice straw,paddy water and brown rice.The kinetics study of pymetrozine residue in water,soil,and rice straw were C = 0.134e~(-0.12t),C = 1.377e~(-0.13t),and C = 0.741e~(-0.10t),respectively.And the kinetics study of thiamethoxam in water,soil,and rice straw were C = 0.114e~(-0.12t),C = 1.118e~(-0.10t),and C = 0.626e~(-0.12t),respectively.The results show that a dosage of 0.0525～0.0788 g/m~2 of 25%pymetrozine and thiamethoxam suspension could be used in rice field ecosystem with harvest interval of 21 days.