ABSTRACT.
Essential oil of Peumus boldus Molina against the nematode Haemonchus contortus (L3) and three stored cereal insect pests

Gonzalo Silva-Aguayo1*, Liliana Aguilar-Marcelino2, Edgar Cuevas-Padilla2, Patricia Loyola-Zapata1, J. Concepción Rodríguez-Maciel3, Gloria Castañeda-Ramírez2, and Inés Figueroa-Cares1
 
Alternative methods of control against different parasites affecting livestock and agriculture are currently being sought. The essential oil of Peumus boldus Molina has anthelmintic and insecticidal activity against the nematode Haemonchus contortus and stored cereal insect pests. The present study aimed to assess the in vitro activity of P. boldus essential oil against H. contortus (L3) unsheathed and Sitophilus zeamais, Tribolium castaneum, and Plodia interpunctella. The essential oil was obtained from leaves of P. boldus and its principal compounds identified by phytochemical analysis. Essential oil was tested at concentrations of 0.25, 0.5, 0.75, 1.0, 1.25, 1.5, 1.75 and 2.0 mgmL-1 on unsheathed L3 H.contortus larvae and in concentrations of 0,35, 70, 100, 125, 150, 175 and 200 μL L-1 air on adult insects. The main constituents detected in the essential oil were1,8-cineole, terpineol, terpinene-4-ol, γ-terpinene, p-cimene, methyleugenol, safrole, (E)-germacrene D, β-tujene, and ascaridol. The nematode H. contortus and insects were exposed to the essential oil for 72 h. In a bioassay with H. contortus larvae, treatment with 2.0 mg mL-1 showed the highest toxicity with 99.2% mortality. Regarding insecticidal activity, S. zeamais was the most susceptible species with a mortality of 90% at 200 μL L-1 air. The present study suggests that the essential oi lof P. boldus has potential anthelmintic and insecticidal activity.
Keywords: Natural products, nematode, Plodia interpunctella, Sitophilus zeamais, stored cereal pests, Tribolium castaneum.
1Universidad de Concepción, Facultad de Agronomía, Av. Vicente Méndez 595, Chillán, Chile.
*Corresponding author (gosilva@udec.cl).
2Instituto Nacional de Investigaciones Forestales y Agropecuarias (INIFAP), CENID-Salud Animal e Inocuidad, km 11 Carretera Federal Cuernavaca-Cuautla, N°8534, Col. Progreso, Jiutepec, Morelos, CP 62550, México.
3Colegio de Postgraduados, Programa de Fitosanidad, Carretera Federal México-Texcoco km 36,5, Texcoco, Estado de México, México.