杀菌剂多菌灵在桑叶中的消解动态研究

多菌灵(carbendazim)是家蚕微粒子病的防治药物。将50%多菌灵可湿性粉剂分别稀释至1000和500倍药液后喷洒桑树,用高效液相色谱(HPLC)检测桑叶中多菌灵的残留和消解动态。结果表明:桑树喷洒稀释1000倍的多菌灵药液后,桑叶中药物的消解动态方程为Ct=4.5339e-0.2215t,药物的半衰期T1/2=3.13d;喷洒稀释500倍的多菌灵药液后,桑叶中药物的消解动态方程为Ct=6.0527e-0.1030t,药物的半衰期T1/2=6.73d。多菌灵在桑叶中的残留与消解动态显示低浓度(稀释1000倍)的药液在桑叶中的降解更快,所以建议生产上适当采用高浓度药液喷施桑树,并根据相应的药物消解动态数据确定桑叶采摘时期,以保证家蚕食下药叶对微粒子病的防治效果。

An Investigation on Digestion Dynamics of Fungicide Carbendazim in Mulberry Leaves

Carbendazim is one kind of systemic fungicides for control of silkworm (Bombyx mori) pebrine disease. In present study,50% wettable powder of carbendazim was diluted 1 000 and 500 times respectively and sprayed onto mulberry leaves. High performance liquid chromatography (HPLC) was used to detect the residue and digestion dynamics of carbendazim in mulberry leaves. The results showed that the dynamic equation of carbendazim digest in mulberry leaves sprayed with 1 000 time dilution was Ct =4. 533 9e-0.221 5t and that of the half-life period was T1/2 = 3. 13 d. The dynamic equation of carbendazim digest in mulberry leaves sprayed with 500 time dilution was Ct =6. 052 7e-0.103 0t and that of the half-life period was T1/2 = 6. 73 d. These results revealed that the carbendazim under 1 000 time dilution had a higher digestion rate in mulberry leaves. Therefore,it is suggested to use relatively higher concentration of carbendazim to spray in mulberry field and choose proper period for mulberry leaf harvesting according to the correspondent chemical digestion dynamics so as to ensure good prevention effect against pebrine disease after silkworm larvae ingest the leaves with fungicide.