Field evaluation of insecticides against insect pests of quinoa and their side effects on non-target species

Over the last few years, quinoa, an Andean crop, has been cultivated at lower elevations including the coastal level where pest pressure is high and farmers resort to intensive use of insecticides. This field study investigated the impact of four insecticides (cypermethrin, imidacloprid, teflubenzuron and emamectin benzoate) on insect pests of quinoa as well as their side effects on the beneficial arthropod community at the coastal level of Peru, by analysing the species composition, species diversity and population density of natural enemies. The arthropod community was examined by a combination of three sampling techniques targeted to taxa from different ecological habitats: pitfall traps for ground dwelling species, plant sampling for phytophagous insects and their natural enemies that inhabit the crop, and yellow pan traps at a height of 1.2 m to catch flying insects. The results demonstrated that Macrosiphum euphorbiae, Frankliniella occidentalis and Spoladea recurvalis were efficiently controlled by cypermethrin and imidacloprid; the latter compound also showed long-term effects on Nysius simulans. Teflubenzuron and emamectin benzoate proved to be efficient to control S. recurvalis. Imidacloprid had the strongest adverse effects on the arthropod community in terms of species diversity, species composition and natural enemy density as compared to the other insecticides. Findings of this study may assist farmers intending to grow quinoa at the coastal level in selecting the most appropriate insecticides under an Integrated Pest Management approach.