Bio-efficacy and dissipation of newer molecules against leafhopper (Amrasca biguttula biguttula) of okra

The bio-efficacy of different insecticides viz., bifenthrin 10 EC at 80 g a. i. ha-1, fipronil 5 SC at 500 g a.i. ha-1, flubendiamide 480 SC at 60 g a. i. ha-1, quinalphos 25 EC at 350 g a.i ha-1, profenophos 50 EC at 400 g a. i. ha-1 and β-cyfluthrin 25 SC at 18.75 g a.i. ha-1 against leafhopper (Amrasca biguttula biguttula Ishida) of okra was studied in the field conditions at Student’s Farm of Agricultural College, Hyderabad during 2012. All the insecticidal treatments were superior over control after second spray where, profenophos (400 g a. i. ha-1) recorded highest population reduction of 68.72 per cent followed by β-cyfluthrin (50.72 %) and bifenthrin (44.19 %). Further, dissipation pattern of profenophos at 400 g a. i. ha-1 was studied by collecting 500 g of okra fruits from the field on zero (1 hr), one, three, five, seven and ten and fifteen days after second spray and analysed at laboratory of AINP on pesticide residues, Hyderabad. An initial deposit of profenophos was recorded to be 1.52 mg kg-1 dissipated to below detectable level on 10th day. The half-life was 2.16 days with waiting period for safe harvest of okra fruit was 5.10 days.