Trichoderma is an important biocontrol agent that produces metabolites harmful to nematodes. We investigated the volatile organic compounds (VOCs) of Trichoderma sp. YMF 1.00416 and examined their abilities to kill nematodes. Chemical investigations of the VOCs from this strain led to the isolation and identification of three metabolites: a new compound, $1{eta}$-vinylcyclopentane-$1{alpha}$,$3{alpha}$-diol (1) and two known metabolites, 6-pentyl-2H-pyran-2-one (2) and 4-(2-hydroxyethyl)phenol (3). Nematicidal activity assays showed that compound 2 was nematicidal, and killed >85% of Panagrellus redivivus, Caenorhabditis elegans, and Bursaphelenchus xylophilus in 48 h at 200 mg/L in a 2 mL vial. Our results will help identify new nematicides.