Abstract

                                Two field experiments were conducted to assess the efficacy of theF9252 (bifenthrin 8% + clothianidin 10% SC) a synthetic pyrethroids andneonicotinoid combination ready mix formulation against white grub andsucking pests of groundnut at Tamil Nadu Agricultural University, Coimbatoreduring February to May 2016 and May - July 2017 using Groundnut varietyTMV 7 in randomized block design (RBD). Applications of insecticides weremade at the time of planting and at 30 days after sowing. Assessment of thephytotoxic effect of F9252 at X, 2X and 4X doses on groundnut crop was alsoevaluated. The results revealed that, the per cent plant mortality due to whitegrub infestation is less than 1 per cent at the plots treated with F9252 @100 + 125 g a.i. ha-1and F9252 @ 80 + 100 g a.i. ha-1 at the time of harvestand it was 14.73 per cent in untreated control. The data on per cent controlof sucking pests (aphids and thrips) indicated that highest per cent controlwas recorded in the treatments, F9252 at 100+125 g a.i. ha-1 and F9252 at80+100 g a.i. ha-1 and these two treatments were comparatively superior toall other treatments. Based on per cent reduction of pest populations overuntreated control the order of relative efficacy of the test insecticides incontrolling the sucking pests were, F9252 @ 100 + 125 g a.i. ha-1 = F9252@ 80 + 100 g a.i. ha-1 > F9252 @ 60 + 75 g a.i. ha-1 = clothianidin @ 125 ga.i. ha-1 = clothianidin @ 100 g a.i. ha-1 > phorate 10 G @ 2500 g a.i. ha-1 =chlorpyrifos 20 EC @ 225g a.i. ha-1 = bifenthrin @ 80 g a.i. ha-1. F9252 at 80 +100, 160 + 200 and 240 + 300 g a.i. ha-1 did not cause any visual phytotoxicsymptoms in both the season of experimentation. The groundnut pod yieldwas maximum in the F9252 @ 100 + 125 g a.i. ha-1(83.10 % increaseover untreated control) and which was statistically on par with the yield ofF9252 @ 80 + 100 g a.i. ha-1 (80.19 % increase over untreated control).Hence, F9252 @ 80 + 100 g a.i. ha-1 is recommended to get maximum yieldwith effective control of groundnut pests in the comparatively low dose ofinsecticide exposure to the environment.

Key words : Groundnut; White grub; Sucking pests; Clothianidin; Bifenthrin