Dissipation of Quinalphos on Cauliflower (Brassica oleracea var. botrytis)

The rate of degradation of quinalphos on cauliflower curds is reported. A field experiment was conducted during Rabi, 2009 following three foliar sprays at 15-days interval @ 500 and 1000 g a.i. ha⁻¹ starting from curd formation stage of the crop. Residues of quinalphos were quantified using GC-FPD. The residues were detected on cauliflower curds till 7^th day after the last spray at recommended and its double dose, respectively. The initial deposits on cauliflower curds were 7.80 and 11.53 μg g⁻¹ at recommended and its double dose, respectively. These were below determination limit on the 10^th day at both the doses. The half-lives (DT₅₀) of quinalphos on cauliflower curds were found to be 1.02 and 1.19 days at recommended and its double dose, respectively. Analysis of soil samples collected on 10^th day after final spray revealed the residues below its determination limit of 0.05 μg g⁻¹ at either dose.