Efficacy of Ultrasound Treatments Against Pine Wood Nematode Bursaphelenchus xylophilus (Steiner & Buhrer 1934) Nickle 1970

The pine wood nematode Bursaphelenchus xylophilus (Nickle, 1970) is one of the most damaging pests affecting coniferous forests, prompting the European Union to adopt strict measures to limit its spread. In sawmills, wood is typically heat-treated following the International Standard for Phytosanitary Measures No. 15 (ISPM 15, 2019), which recommends heat treatment or fumigation with methyl bromide or sulfuryl fluoride for wood packaging materials including pallets, crates, and dunnage. To investigate safer and more cost-effective alternatives, this study uses ultrasound technology as a potential control method. Ultrasound, defined as high-frequency sound waves beyond human hearing, generates acoustic cavitation capable of damaging biological tissues. Nematodes were exposed to ultrasound both in vitro and within artificially inoculated green wood blocks (50 × 50 × 50 mm). In vitro tests showed significant reductions in viability at the measured time points (15, 30, 45 min), with complete mortality observed at 45 min. In wood blocks, nematode numbers declined progressively across the measured intervals, with linear regression providing a model-based estimate of complete elimination before approx. 80 min, although this was not experimentally verified. These results demonstrate that the use of ultrasound at 40 kHz reduces nematode survival under both laboratory conditions and wood matrix conditions.