ANALYSIS OF SELECTED PESTICIDES (I.E. IMIDACLOPRID AND DIMETHOATE) RESIDUE IN YARD LONG BEANS (VIGNA UNGUICULATA SUBSP. SESQUIPEDALIS) AND OKRA (ABELMOSCHUS ESCULENTUS L. (MOENCH)
Yumnam Devashree, B.K.Dutta, L. Shanjukumar Singh and A. Robinson Singh
A study was conducted to analyse the residues of some selected pesticides (i.e. Imidacloprid and Dimethoate) on the okra fruits (Abelmoschus esculentum L. (Moench)) and yard long bean (Vigna unguiculata subsp. sesquipedalis) with the help of HPLC. The purpose of the experiment was to determine the interval between spraying and harvest required for the safe use of these crops to prevent any health problems to the consumers. During the month of October and November 2014, yard long bean samples were taken at 3, 7, 10, 15 and 21 days after spraying with the pesticide and okra/lady’s finger were plucked at 3, 8 and 14 days after spraying. The half life of imidacloprid on yard long beans and okra fruits was calculated to be 2.08 and 2.66 days respectively. The half life of dimethoate was calculated at 3.7 days on yard long beans and 2.45 days on okra fruits. The concentration of pesticide residues declined gradually. The degradation of the pesticides on yard long beans followed second order kinetics while that on lady’s finger followed first order kinetics.