Evaluación de la toxicidad de extractos de Brugmansia arborea (L.) Lagerh, 1895 y Salix humboldtiana (Willdenow, 1806) para el control de Spodoptera frugiperda (J. E. Smith, 1797) en condiciones de laboratorio Pamplona, Norte de Santander, Colombia.

Abstract

The objective of the bioassay was to evaluate the toxicity of aqueous plant extracts of floripondium and weeping willow on second-instar larvae of Spodoptera frugiperda (J. E. Smith), under laboratory conditions. In a completely randomized experimental design, concentrations of 100,000, 75,000, 50,000, and 25,000 mg/L of floripondium and weeping willow extracts, the insecticide lambdacyalothrin (1 ml/L) and a control were evaluated. The plant extracts with five repetitions per concentration, and each repetition with ten larvae of S. frugiperda, obtained from a laboratory breeding (17±1°C and 65±10% RH). To determine mortality, observations were made every 12 hours. The data were analyzed using SPSS software, performing Tukey Tests. To calculate the LC50, concentrations were transformed to log10 and mortalities to Probit. Using the accumulated mortalities until the time of death, the TL50 was determined through a Regression Analysis. The insecticide lambdacyalothrin (1.0 ml/L) and the extracts of S. humboldtiana and B. arborea at 100,000 mg/L caused mortalities of 100%, 98% and 96%, respectively; significantly different from the other treatments. The LC50 for S. humboldtiana was 9.772 mg/L and for B. arborea it was 11.759 mg/L; The TL50 of the two extracts are very similar, for B. arborea they were 25,000 mg/l, 138; 50,000 mg/L, 68; 75,000 mg/L, 55; 100,000 mg/L, 46 hours; while for the S. humboldtiana extracts they were 25,000 mg/L, 166; 50,000 mg/L, 80; 75,000 mg/L, 64; 100,000 mg/L, 45 hours. The pyrethroid insecticide lambdacyhalothrin (1.0 ml/L) and weeping willow and floripondium extracts (100,000 mg/L) were highly effective against S. frugiperda larvae, with mortalities of 100%, 98% and 96% respectively. The extracts of S. humboldtiana and B. arborea showed potential as phytochemicals in the integrated management of S. frugiperda.