Study on Residue of Chlorpyrifos and Bifenthrin in Field Soil Simulating House Termite Prevention Treatment

The residue of chlorpyrifos and bifenthrin in field soil at different dosage and treatment with or without covering was studied at termiticidal application rates.The results showed that bifenthrin was more stable than chlorpyrifos.The rate of degradation of two termiticides in treatment with covering was slower than without covering and the initial concentration of termiticides in soil had important effect on their degradation rate.The half-life of chlorpyrifos in 30 g/m~2 and 20 g/m~2 treatment with covering was 186.3 days and 171.3 days,but it was decreased to 60.2 days in 30 g/m~2 treatmentwithout covering.As for bifenthrin,the half-life was 302.6,203.3,107.0 days respectively in order in 1.875 g/m~2 and 1.250 g/m~2 treatment with covering and 1.875 g/m~2 treatment without covering.