Abstract: A HPLC method was used to explore degradation behavior and environmental safety of 10% fenoxaprop-p-ethyl·cyhalofop-butyl EC(Baichu) in rice.Results indicate that 1) degradation of fenoxaprop-p-ethyl and cyhalofop-butyl in paddy water,soil and rice plant all accorded with the one-level dynamic equation;2) the half-life of fenoxaprop-p-ethyl in paddy water,soil and rice plant were 3.51,1.63 and 2.14 d,respectively;3)the half-life of cyhalofop-butyl in paddy water,soil and rice plant were 3.18,1.61 and 2.05 d,respectively;and 4)when Baichu was applied at the recommended dose,residues of the two effective components were both lower than MRL.

Key words: Baichu, fenoxaprop-p-ethyl, cyhalofop-butyl, rice, soil, residue