Volatile Organic Compounds from <i>Wolfiporia hoelen</i> Exhibit Nematicidal Activity Against <i>Bursaphelenchus xylophilus</i>

Pine wilt disease, caused by the pinewood nematode (PWN) Bursaphelenchus xylophilus, devastates pine forests worldwide. Although the medicinal fungus Wolfiporia hoelen exhibits nematicidal activity against PWN, its specific bioactive constituents remain unidentified. This study investigated the nematicidal activity of volatile organic compounds (VOCs) released from W. hoelen against PWN. Results indicated that VOCs from W. hoelen exhibit significant inhibitory efficacy against second-stage juveniles (J2s) of PWN, achieving 90% mortality after 72 h of exposure. In contrast, ovicidal activity was limited (6% hatching inhibition after 24 h). To analyze the VOCs produced by W. hoelen via solid-phase microextraction gas chromatography–mass spectrometry (SPME-GC-MS), we identified six major and commercially available VOCs: (Z)-5-octen-1-ol, 1-octen-3-ol, 3-octanol, 3-octanone, phenylglyoxal, and phenylacetaldehyde. Five compounds (excluding phenylglyoxal) exhibited nematicidal activity against PWN J2s through both contact and fumigation. These findings demonstrate the efficacy of W. hoelen and its VOCs as promising candidates for management of PWN.