Dissipation of Spiromesifen in/on Okra under Middle Gujarat Conditions

With a view to study the dissipation of spiromesifen in/on okra, a field experiment was conducted at the Main Vegetable Research Station, Anand Agricultural University, Anand during kharif, 2008. The foliar application of the insecticide was carried out twice at 10 d interval @ 120 and 240 g a.i. ha⁻¹ at fruiting stage of the crop. Samples of okra fruits were drawn at 0, 1, 3, 5, 7, 10, 15 and 20 d after second spray. Soil samples were also collected on 20^th d after second application. The initial deposits of spiromesifen on okra fruits were 0.964 and 1.819 mg g⁻¹ at standard and double the standard dose of application, respectively. The residues gradually declined and persisted upto 3^rd and 5^th d at lower and higher dose, respectively. The residues reached below quantitation limit of 0.01 μg g⁻¹on the 5^th and 7^th d at standard and double the standard dose, respectively. Halflife of the insecticide on okra fruits was 1.68 and 1.65 d for standard and higher dose, respectively. Soil samples analyzed on the 20^th d after the last spray revealed residues at below quantitation limit of 0.01 μg g⁻¹ at either dose of application.