title: Bioactivity against Bursaphelenchus xylophilus: Nematotoxics from essential oils, essential oils fractions and decoction waters.
abstract: The Portuguese pine forest has become dangerously threatened by pine wilt disease (PWD), caused by the pinewood nematode (PWN), Bursaphelenchus xylophilus. Synthetic chemicals are the most common pesticides used against phytoparasitic nematodes but its use has negative ecological impacts. Phytochemicals may prove to be environmentally friendly alternatives. Essential oils (EOs) and decoction waters, isolated from 84 plant samples, were tested against B. xylophilus, in direct contact assays. Some successful EOs were fractionated and the fractions containing hydrocarbons or oxygen-containing molecules tested separately. Twenty EOs showed corrected mortalities ⩾96% at 2 μL/mL. These were further tested at lower concentrations. Ruta graveolens, Satureja montana and Thymbra capitata EOs showed lethal concentrations (LC100)<0.4μL/mL. Oxygen-containing molecules fractions showing corrected mortality ⩾96% did not always show LC100 values similar to the corresponding EOs, suggesting additive and/or synergistic relationships among fractions. Nine decoction waters (remaining hydrodistillation waters) revealed 100% mortality at a minimum concentration of 12.5μL/mL. R. graveolens, S. montana and T. capitata EOs are potential environmentally friendly alternatives for B. xylophilus control given their high nematotoxic properties. Nematotoxic activity of an EO should be taken in its entirety, as its different components may contribute, in distinct ways, to the overall EO activity.
authors.affiliation: Universidade de Lisboa, Faculdade de Ciências de Lisboa, DBV, IBB, Centro de Biotecnologia Vegetal, C2, Campo Grande, 1749-016 Lisboa, Portugal.
authors.forename: Jorge M S
authors.initials: JM
authors.lastname: Faria
authors.forename: Pedro
authors.initials: P
authors.lastname: Barbosa
authors.forename: Richard N
authors.initials: RN
authors.lastname: Bennett
authors.forename: Manuel
authors.initials: M
authors.lastname: Mota
authors.forename: A Cristina
authors.initials: AC
authors.lastname: Figueiredo
mesh_terms: D000818:Animals; D005591:Chemical Fractionation; D016000:Cluster Analysis; D004305:Dose-Response Relationship, Drug; D006790:Host-Parasite Interactions / Q000187:drug effects; D019686:Lamiaceae / Q000737:chemistry; D009348:Nematoda / Q000187:drug effects* / Q000502:physiology; D009822:Oils, Volatile / Q000145:classification / Q000302:isolation & purification / Q000494:pharmacology*; D028223:Pinus / Q000469:parasitology; D010935:Plant Diseases / Q000469:parasitology; D010936:Plant Extracts / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology; D010938:Plant Oils / Q000145:classification / Q000302:isolation & purification / Q000494:pharmacology*; D010944:Plants / Q000737:chemistry* / Q000145:classification; D032105:Ruta / Q000737:chemistry; D031362:Satureja / Q000737:chemistry; D013045:Species Specificity; D014867:Water / Q000737:chemistry
chemical_list: D009822:Oils, Volatile; D010936:Plant Extracts; D010938:Plant Oils; D014867:Water
keywords: 2-Undecanone; Bursaphelenchus xylophilus; Carvacrol; Decoction waters; Essential oils; Hydrocarbon molecules; Nematotoxic; Oxygen-containing molecules; Pinus pinaster; γ-Terpinene