Pesticide Residue Laboratory Department of Entomology, Assam Agricultural University, Jorhat-785 013, Assam, India
*Present address: Soil & Water Management Department, Tocklai Experimental Station, Tea Research Association, Jorhat - 785 008, India.
Online published on 3 November, 2011.
Dissipation of residues of quialphos was studied in/on brinjal fruits under field conditions. The insecticide (Ekalux 20 AF) was applied 35 d after transplanting by foliar spraying @ 0.5 (T1) and 1.0 kg a.i. ha−1 (T2). In all, four sprays were given at 15 d interval. At either rate, the cummulative residues of the insecticide in/on marketable size brinjal fruits sampled one h after the last spray ranged from 1.26 to 1.79 mg kg−1. These dissipated with half-life values of 2.1 to 2.2 d and reached below detectable levels in 15 d after last spray. Brinjal fruit samples of 2–7 d in T1 and 1–7 d in T2 showed presence of quinalphos oxon in addition to the parent compound in amounts ranging from 0.02 to 0.09 mg kg−1. The safe waiting periods were found to be 4.9 and 6.1 d for the two treatments. Washing coupled with rubbing under tap water dislodged 76% residues from the treated fruits.
Brinjal (egg plant), Solatium melongena, quinalphos, quinalphos-oxon, reridues
