Bioactivity against Bursaphelenchus xylophilus: Nematotoxics from essential oils, essential oils fractions and decoction waters

Ruta graveolens, Satureja montana and Thymbra capitata essential oils showed high nematotoxic activities against Bursaphelenchus xylophilus. Activities from fractions containing hydrocarbon- or oxygen-containing molecules suggested additive and/or synergic relations. •Pine wilt disease (PWD) is caused by the pinewood nematode (PWN), Bursaphelenchus xylophilus.•84 essential oil samples were evaluated against Bursaphelenchus xylophilus.•Ruta graveolens, Satureja montana and Thymbra capitata essential oils showed PWN toxicity.•Essential oils oxygen-containing molecules fractions were more effective in most cases.•In addition, the hydrocarbon fraction also plays an important role in PWN toxicity. 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)