Fate of hexythiazox residues in tea leaves

Fate of hexythiazox 5.45 EC residue was evaluated in tea leaves after application @ 25 and 50 g a.i. ha⁻¹ to derive the safe preharvest waiting period with two field trials. Leaf samples (250 g) were collected on 0, 1, 3, 5, 7 and 10 days after third round of application. The residue estimated by High Performance Liquid Chromatography revealed that for the two doses of hexythiazox evaluated residues were 0.0933 and 0.2035 μg g⁻¹, respectively in the field trial I and 0.1113 and 0.1848 μg g⁻¹, respectively in the field trial II. The residues reached below detectable level on 5^th and 7^th day after application for the doses evaluated. Half-life of hexythiazox was observed to range from 1.10 to 1.82 days. A safe waiting period of 3.8 days might be recommended for harvesting the leaves after spraying hexythiazox @ 50 g a.i ha¹.