【摘要】 溴氰菊醋在田间条件下在茶树新梢上降解很缓慢,低于二氯苯醚菊酯;它在叶表的渗透力较弱。以每亩0.44—0.73克有效成份用量(合2.5％乳剂6000—10,000倍液)喷施茶树后,鲜叶中原始附着量(以鲜叶干重计)为1.34—3.23ppm。溴氰菊酯在鲜叶和成茶中的半衰期(按原始附着量计算)均为2.8天。气候条件对溴氰菊酯降解的影响较小,但如喷药后1-2天遇雨会加速溴氰菊酯残留量的降解。由于溴氰菊酯的蒸气压特低,因此鲜叶中的残留量通过加工过程的降解率很低,平均仅为29.79%。由于溴氰菊醋在水中溶解度很低,因此,成茶中的残留农药,在泡茶过程中,进入茶汤中的数量,不会超过其中含量的1％。 根据已报道的溴氰菊酯的ADI值,作者建议溴氰菊酯在成茶中的暂定允许残留标准为2ppm,茶树喷施2.5％乳剂 6000—10,000倍液时的安全间隔期为3天,这样通过茶汤进入人体的量不会超过0.02ppm。更多还原

【Abstract】 Eesults from the laboratory and field experiments carried out in 1979-1980 showed that Decis performed outstanding effectiveness against lepidopterous larvae and jassids infecting tea. Its LD50 and LD95 to mature larvae of the tea looper caterpillar Ectropis obliqua Warren were 4.95±0.11 ng/g and 25.12±1.45 ng/g respectively. In the field conditions, Decis degraded very slofwly on teashoots, and was even more slower than Permethrin. The penetrating ability of Decis was also relatively weak. When used at 0.44-0.73 g a.i. per mμ (2.5% EC 6000-10000 dilutions), the half life (HI50) of Decis in fresh leaves and made tea was 2.8 days together (calculated with the initial deposit). Weather conditions showed slight influences. Owing to the low vapour pressure, the degradative rate of the residues of Decis in the course of tea manufacture was relatively low (29.79% in average). The extractive percentage of Decis residues in made tea with infusion procedure was lower than 1%.Based on the no-effect level value reported by Eousell Uclaf Ltd. in France, the authors propose the permitted residue limit in the made tea to be 2 ppm. According to this limit, the safety interval should be 3 days after the use of 1:6000-10000 dilute solutions of 2.5% EC Decis. If it was applied with the low-volume or ultra low-volume spraying methods, the safety interval should be delayed to 5 days.更多还原