Persistence Behaviour of Milbemectin in/on Tea Under North-East Indian Climatic Condition

A multi-location field trial was conducted under North-East Indian climatic condition viz. Siliguri and Dooars, West Bengal, India during Monsoon 2005 to evaluate the dissipation pattern of Milbemectin formulation (Milbeknock 1% EC) in/on tea field at two application rates (5 and 10 g a.i. ha −1 ). The quantitative analysis was performed using High Performance Liquid Chromatography (HPLC) with fluorescence detection at 460 nm. Following the first order kinetics the acaricide dissipates with half-life (T 1/2 ) value ranges between 4.93–5.28 days and 6.84–10.76 days in made tea samples of Siliguri and Dooars field, respectively.