Impacto de Doru luteipes na supressão de Spodoptera frugiperda E Puccinia sorghi na cultura de milho

Abstract

The fall armyworm (Spodoptera frugiperda, Lepidoptera: Noctuidae) and common corn rust caused by Puccinia sorghi (Pucciniales: Pucciniaceae) represent a threat to corn productivity in Brazil. The earwig Doru luteipes (Dermaptera: Forficulidae) is an omnivorous and mycophagous predator naturally present in this crop, feeding on S. frugiperda and uredospores of Puccinia sp. However, the effective ecological role of this predator in suppressing pests and fungal structures in corn, as well as the implications of its omnivorous and mycophagous habits, remain poorly elucidated. In this dissertation, we conducted a systematic review to synthesize the biotic, abiotic, and ecological factors that modulate the food selection and role of Dermapterans as biological control agents. Additionally, we experimentally evaluated the impact of D. luteipes' omnivory and mycophagy on the dynamics of S. frugiperda and P. sorghi in free-choice and no-choice feeding assays among S. frugiperda eggs and neonate larvae, corn pollen, and P. sorghi uredospores, as well as the disease dispersal capacity on corn plants by D. luteipes after feeding on exclusive and mixed diets containing P. sorghi uredospores and S. frugiperda eggs and neonate larvae. We also evaluated the attraction of D. luteipes to volatiles from corn plants infested by S. frugiperda and/or infected by common corn rust at different stages of the infectious disease process. The results demonstrated that D. luteipes, under freechoice conditions, exhibited a preference for S. frugiperda neonate larvae, although it consumed all available food sources. In the absence of choice, D. luteipes consumed each of the available foods significantly. The consumption of viable P. sorghi uredospores significantly reduced their viability, resulting in lower infection and cumulative progression of foliar lesions over time. In olfactometer tests, the predator was attracted to volatiles from plants infested by S. frugiperda and from co-infected plants at the early disease stage. These findings clarify the ecological impact of D. luteipes' omnivory-mycophagy and its role in suppressing S. frugiperda and P. sorghi, opening perspectives for integrated management strategies that synergistically incorporate this biological control agent in the simultaneous suppression of both threats.