[Residue decline dynamics and safety utilization of carbendazim in cultivation of Anoectochilus roxburghii].

The paper aimed to study the residue decline dynamic and standards for safety utilization of carbendazim in roots, stems, leaves of Anoectochilus roxburghii and in growth media. Samples extracted with methanol were purified by liquid-liquid extraction and analysed by HPLC. The results showed that average rate of recovery was 82.9% - 95.7% and RSD were 2.0% - 6.3% with add of carbendazim in respectively diverse concentration, which meets inspection requirement of pesticide residue. Two kinds of dosages of carbendazim were treated, varying from recommended dosage (1.0 kg x hm(-2)) to 1.5 times recommended dosage (1.5 kg x hm(-2)). Results of two years test showed that the half-life period of carbendazim were 7.01 - 8.51 d in the growth media of A. roxburghii, 3.58 - 4.27 d in stems and 3.50 - 3.91 d in leaves, 4.93 - 5.71 d in roots. Providing max recommended residue of carbendazim in the cultivation of A. roxburghii is 0.5 mg x kg(-1), sprayed 4 times a year with the dosage of 1.0 kg x hm(-2), 28 days is proposed for the safety interval of the last pesticide application's and harvest's date.