Efficacy and safety-evaluation of insecticidal modules against Spodoptera frugiperda (Lepidoptera: Noctuidae) and the residues of the most effective schedule in maize

Abstract

The appearance and rapid spread of the fall armyworm (Spodoptera frugiperda) (FAW) represents a serious threat to maize cultivation in India and elsewhere in South Asia. Chemical control illustrates one of the major means of reducing the infestation of FAW in maize-growing zones. However, existing information regarding the field-efficacy and non-target toxicity of different insecticides against this pest is not adequate and is also unable to capture the momentum change in the scenario of residual toxicity and insecticide resistance for redacting sustainable management. The present study was framed to establish the most suitable insecticidal schedule against FAW for maize producers. In the period from winter 2019–2020 to spring–summer 2020, seven treatment schedules against FAW were evaluated, and the efficacy was calculated according to the per cent maize plant damage (PD) by larvae, while safety was enumerated based on larval parasitization by Campoletis chlorideae and the abundance of coccinellid predators. In both seasons, the highest cumulative efficacy (9.88 and 10.19% PD) was confirmed for T3 (constituted with Barazide®, Delegate®, and Ampligo®) with a significantly higher yield (52.39 and 52.66 q ha−1), whereas T7 (Proclaim Fit®, Ampligo®, and Delegate®) and T6 (Fimecta®, Ampligo®, and Spintor®) exhibited a high cumulative efficacy (11.06 to 12.23% PD). T3 was found to be safe to coccinellid predators and the per cent larval parasitism by C. chlorideae was significantly higher in this module (2.57 and 2.75%) compared to T4 and T5 (1.00 to 1.67%). The residues of Barazide®, Delegate®, and Ampligo® were below detectable levels in maize plant, grain and soil samples. Therefore, the module could be recommended against FAW in the near future.