Search for pinewood nematode control using essential oils isolated from Portuguese aromatic flora

Abstract

The pinewood nematode (PWN), Bursaphelenchus xylophilus, is a major worldwide Pinus pathogen and pest, with impact on forest health, natural ecosystem stability and international trade. Essential oils (EOs) may be an alternative to the current control options. Seventy three EOs from 46 species from the Portuguese aromatic flora were screened for in vitro nematicidal activity against PWN. The suitability of Triton X-100 or acetone as EOs diluting agent was assessed; accuracy of results using the two solvents was compared and the latter found preferable. One hundred percent mortality was achieved with EOs from Chamaespartium tridentatum, Origanum vulgare, Ruta graveolens, Satureja montana, Thymbra capitata and Thymus caespititius at concentrations ranging between 0.5 and 2.0 mg/mL, and those oils analyzed by GC and GC-MS. The dominant components of the effective oils were 1 octen-3-ol (9%), n nonanal and linalool (both 7%) in C. tridentatum, carvacrol (36% and 39%), γ-terpinene (24% and 40%) in O. vulgare and S. montana, 2-undecanone (> 90%) in R. graveolens and carvacrol (75% and 65%) in T. capitata and Th. caespititius. Jorge Faria is grateful to the FCT for the PhD grant SFRH/BD/43738/2008. Partially funded by FCT under research contract PTDC/AGR-AAM/74579/2006.