AVALIAÇÃO DA ASSOCIAÇÃO DE FUNGOS ENTOMOPATOGÊNICOS COM O ÓLEO DE MAMONA NO MANEJO DE Spodoptera frugiperda EM MILHO

Abstract

The fall armyworm, Spodoptera frugiperda, is a key pest of maize in Brazil, reinforcing the need for alternatives to chemical control. This study evaluated the association of the entomopathogenic fungi Beauveria bassiana and Metarhizium anisopliae with castor oil (2%) on infestation, foliar damage, and larval mortality. Experiments were conducted under field and laboratory conditions. In the field, the proportion of infested plants and the intensity of defoliation were assessed following treatment applications at the vegetative stage. In the laboratory, larval mortality was evaluated over 12 days. Data were subjected to ANOVA, with arcsine√(p) transformation when necessary, and means were compared using Tukey’s test (5%). Field assessments indicated low infestation levels (<0.5%) and no consistent differences among treatments, with only punctual reductions of no agronomic relevance. In the laboratory, mortality ranged from 0 to 18.75%, with no significant differences among treatments, although some combinations of Metarhizium anisopliae and castor oil showed numerically higher values. Literature and laboratory findings indicate that environmental factors particularly high UV radiation, dry weather, and low humidity limited fungal performance under field conditions. It is concluded that the evaluated fungi are promising for preventive and integrated applications, although they show limitations when used alone under field conditions.