Insect Growth Regulators (IGRS): A novel tool to regulate soybean defoliators

Assessment of various concentrations of insect growth regulators (IGRs) in soybean were evaluated against lepidopterous defoliators (Spilarctia obliqua Walk., Spodoptera litura Fab. and Thysanoplusia orichalcea Fab.) and their efficacy was compared with monocrotophos (800 ml ha⁻¹). Four doses viz., 200 g ha⁻¹, 300 g ha⁻¹, 400 g ha⁻¹ and 600 g ha⁻¹ for diflubenzuron (Dimilin 25 WP) and 200 ml ha⁻¹, 400 ml ha⁻¹, 600 ml ha¹ and 800 ml ha⁻¹ for lufenuron (Match 5 EC) were used. The population of defoliators decreased significantly in IGRs as compared to control whereas it was at par with monocrotophos. The larval population was effectively suppressed after 3, 7 and 10 day of second spray in both cases. Diflubenzuron @ 600 g ha⁻¹ followed by 400 g ha⁻¹, monocrotophos @ 800 ml ha⁻¹ and lufenuron @ 800 ml ha⁻¹was most effective treatment in suppressing these defoliators after 10^th day of second spray.