【摘要】 本文是介绍有机磷农药乐果及其主要代谢物氧乐果在茶树上的残留降解动态。根据实验结果,在自然条件下,乐果在茶树芽梢上的降解速度中等。喷施800倍和1600倍药液后,芽梢中的乐果含量10天后可降至<0.5ppm和<0.05ppm。干茶中的乐果含量5天后降至<1.0ppm以至0.7ppm,9天后降至<0.1ppm。在喷施乐果的茶树芽梢上可检出其氧化物一氧乐果。喷药后3—5天达最高值,以后渐降,6—9天后即降至<ppm。干茶中氧乐果含量在喷后第三天最高,约为1ppm,第6—9天降至<0.1ppm。成茶中的乐果在泡茶过程中进入茶汤的比例为41.4%。据本实验结果参照联合国FAO/WHO会议提出的ADI资料,作者建议茶叶中乐果残留量(乐果+氧乐果总量)允许标准订为1ppm。如按此标准,则喷施40%乐果乳油800倍和1600倍液后7天和5天,成品茶中残留量即可低于1ppm。但因喷施乐果后对茶叶品质有影响,故建议:喷施2000倍液安全间隔期为7天;喷施1000倍液安全间隔期为10天。更多还原

【Abstract】 Dimethoate has been widely used for the control of tea pests suchas jassids,aphids and thrips etc.The present paper deals with the stu-dies on the degradation of dimethoate and dimethoxon in tea shoots.Acording to the results of experiment,it is concluded that underthe natural field conditions,dimethoate degrades moderately on thefresh tea-shoots.After the spraying of 40% dimethoate EC at dilutionof 1:800 and 1:1600,it decreases to less than 0.5 ppm and less than0.05 ppm respectively after 10 days.The residue of dimethoate in themade green tea decreases to less than 1.0 ppm and 0.7 ppm respecti-vely 5 days after the application,and decreases to less than 0.1 ppmafter 9 days.Results indicate that the P=0 analoga(dimethoxon)canbe detected in the tea shoots which sprayed with dimethoate.Thereare less than 0.1 ppm to 0.27 ppm initially and increases graduallyand reaches the maximum at the 3-5 days after application then decrea-ses to less than 1 ppm about 6-9 days.The residue of dimethoxon in themade green tea reaches the maximum of about 1 ppm at the 3rd daysafter application and decreases to less than 0.1 ppm at 6th-9th days.The extraction percentage of dimethoate residue in the made tea withthe infusion procedure is relatively high about 41.4%.According to the results of investigation,the authors recommen-ded that the tolerance residue limits in the made tea may be establishedas 1 ppm(expressed as the sum of dimethoate and dimethoxon).Ac-cording to this,the residue of dimethoate and dimethoxon in the madetea which manufactured by the tea-shoots sprayed with 40% dimethoatEC at a dilute of 800 and 1600 may be decreases to less than 1 ppmafter 7 days and 5 days after the application.However,owing to thetiants of dimethoate to the made tea,so that the authers recommen-ded that the safety intervals should be delayed to 7 days(40% EC 2000dilute solution)and 10 days(40% EC 1000 dilute solution).更多还原