Spodoptera frugiperda (Lepidoptera: Noctuidae) infestation in maize and its management using mulberry organic residues

Abstract

Introduction. Soil incorporation of Morus alba biomass mitigates Spodoptera frugiperda damage in maize, through the release of bioactive secondary metabolites with antifeedant properties. Objective. To characterize farmer perceptions of Spodoptera frugiperda severity and evaluate the efficacy of Morus alba residue incorporation as a sustainable management strategy in the Mocache canton, Ecuador. Materials and methods. The research was conducted between December 2023 and May 2024. The study consisted of two phases: a survey of farmers and a field experiment. The farmers were surveyed regarding the agronomic practices they implemented to manage S. frugiperda. The experiment was conducted in the locality of Jesús del Gran Poder and consisted of three treatments: i) a control without pest management or residue incorporation (Control); ii) soil incorporation of 1 t ha⁻¹ of a mixture of maize residues (80 %) and fragmented mulberry cv. Tigreada (20 %) (M+M); and iii) the application of methomyl insecticide. The variables of severity of infestation and agricultural yield were evaluated. A randomized complete block design with three treatments and three replicates was employed. Treatment means were compared using Duncan’s multiple range test (α = 0.05). Statistical processing was performed using the InfoStat package. Results. Residue incorporation reduced severe foliar damage (grades 4-5) to 29.6%, significantly lower than the control (36.1%; p < 0.05). Grain yield reached 4.1 t ha⁻¹ with residues, statistically comparable to methomyl (4.6 t ha⁻¹) and 17 % higher than the control (3.5 t ha⁻¹). Conclusions. The high perception of severity of S. frugiperda by farmers corresponds with high levels of infestation, associated with inadequate agronomic practices and poor technical training. The maize and mulberry residues incorporated into the soil reduce severity and allow obtaining yields like the insecticide, validating its effectiveness as a management alternative in Ecuador and similar regions.