Resumo

FLORES-VILLEGAS, M. Y. et al. Evaluating the methanolic extract of Datura metel as a biorational insecticide for controlling Neodiprion autumnalis S. (Hymenoptera: Diprionidae). Quebracho (Santiago del Estero) [online]. 2020, vol.28, n.1, pp.34-42.  Epub 01-Jun-2020. ISSN 0328-0543.

Pine defoliators are considered an important forest pest whose damage is underestimated due to the damage caused by others such as debarkers and parasitic plants. For the control of pests, there exist bioactive plants belonging to the Solanaceae family within which Datura metel is found. This work aimed to determine larvae mortality in the fourth instar of N. autumnalis and to establish the level of toxicity of leaf, stem and root methanolic extracts of D. metel, on populations of Pinus leiophylla Schl. y Cham. Thus, the toxicity of the leaf, stem and root methanolic extracts of D. metel L. (Solanales: Solanaceae) were evaluated on fourth instar larvae of the N. autumnalis S. pine defoliator at different concentrations (1, 10, 50 and 100 mg/L). Mortality values were recorded at every 2 h intervals (0 to 24 h) since the larvae were exposed to the methanolic extracts. The highest toxic effect was that on the root extract (86.0 % mortality, LC50 of 3.68 mg/L), followed by that on leaves (83.3 %, CL50 4.98 mg/L), and stem (80.0 %, LC50 of 12.79 mg/L), which is very useful for managing forests pests. The untreated extracts of leaves, stems and roots of D. metel contain alkaloids, which interrupt the life cycle of fourth instar larvae of N. autumnalis, so they can be used as biocides.

Palavras-chave : Forest; Datura metel; extracts; pest; secondary metabolites.