Bioactivity of Peumus boldus Molina, Laurelia sempervirens (Ruiz & Pav.) Tul. and Laureliopsis philippiana (Looser) Schodde (monimiacea) essential oils against Sitophilus zeamais Motschulsky

Carmen Herrera-Rodríguez1, Carolina Ramírez-Mendoza1, Itzel Becerra-Morales1, Gonzalo Silva-Aguayo2*, Angélica Urbina-Parra2, Inés Figueroa-Cares2, Luciano Martínez-Bolaños1, J. Concepción Rodríguez-Maciel3, Angel Lagunes-Tejeda3, Edgar Pastene-Navarrete4, and Luis Bustamante-Salazar4
The maize weevil (Sitophilus zeamais Motschulsky) is one of most important pest of stored seeds worldwide, but its current control method is based on the use of synthetic insecticides, usually leading to undesirable problems such as insecticide residues on treated food, human intoxications, and insect resistance development. Therefore the search of friendly alternative methods is required. The aim of this study was to assess, under laboratory conditions, the insecticidal properties of Peumus boldus Molina, Laurelia sempervirens (Ruiz & Pav.) Tul., and Laureliopsis philippiana (Looser) Schodde essential oils against S. zeamais. The phytochemical analysis of the three essential oils showed 1,8-cineole, safrole and methyleugenol as the common components; all of them documented with insecticidal activity from essential oils from other plant species. The highest toxicity (100% mortality) of these three oils acting as a contact insecticide was observed at 24 h exposure at 4% concentration. The estimated LC50 values for P. boldus, L. sempervirens, and L. philippiana were 0.37, 1.02, and 0.28 µL g-1, respectively. Peumus boldus exhibited the highest fumigant activity with 100% adult mortality at 30 µL oil L-1 air. At ≥ 0.5% (v/w) concentration, all essential oils showed repellent activity. These three essential oils showed a promissory insecticidal activity against the maize weevil.
Keywords: Botanical insecticides, essential oils, maize weevil, stored grains.
1Universidad Autónoma Chapingo, Departamento de Parasitología Agrícola, km 38,5 Carretera México-Texcoco, Texcoco, México.
2Universidad de Concepción, Facultad de Agronomía, Av. Vicente Méndez 595, Chillán, Chile. *Corresponding author (gosilva@udec.cl).
3Colegio de Postgraduados, Campus Montecillo, km 36,5 Carretera México-Texcoco, Texcoco, México.
4Universidad de Concepción, Facultad de Farmacia, Víctor Lamas 1290, Concepción, Chile.