Potencial insecticida de especies de paramo frente a la mosca blanca (Bemisia tabaci) asociadas a cultivos de frijol

Abstract

The objective of this study was to evaluate the insecticidal potential of 14 plant species from the páramo against the whitefly (Bemisia tabaci), a pest that affects short-cycle crops such as beans. The chemical composition of the species was preliminarily characterized through phytochemical analyses and the quantification of secondary metabolites, revealing a higher abundance of polyphenols and a lower concentration of flavonoids. Additionally, the presence of phenolic compounds, tannins, and carotenoids was confirmed. An insecticidal bioassay was standardized by spraying plant material leaves with ethanolic extracts from 14 páramo plant species at a concentration of 35 mg/L. The results identified insecticidal activity against Bemisia tabaci and prioritized the species Scutellaria coccinea and Macleania rupestris, with the latter standing out for exhibiting a 58% corrected mortality rate 24 hours after exposure. Additionally, the Analytic Hierarchy Process (AHP) was used to prioritize the species based on criteria of mortality, distribution, and chemical profiles. The Macleania rupestris extract was selected for fractionation by vacuum liquid chromatography, yielding fractions of varying polarity. The ethyl acetate fraction exhibited the highest insecticidal activity (100% at 24 hours) and was therefore analyzed by gas chromatography coupled with mass spectrometry, which allowed for an assessment of its chemical composition through the tentative identification of secondary metabolites of interest, including lupeol acetate and isocitronellol, as well as other compounds such as palmitic acid and ethylene brasilate. The results suggest that the compounds present in the medium- and high-polarity fractions of the páramo plant species could contribute to their insecticidal activity, demonstrating their potential as a source of biopesticides for the sustainable management of agricultural pests and the reduction of agrochemical use.