Optimizing Large-Scale Hot Water Treatment: Evaluating the Thermal Sensitivity of Pratylenchus penetrans and Heat Damage to Perilla frutescens and Two Widely Traded Ornamental Plants

In East Asia, especially in South Korea, Perilla frutescens L. is widely cultivated for food and industrial uses. Root-lesion nematodes, particularly Pratylenchus penetrans Cobb, are significant pests in Korean perilla fields, leading to chlorosis, root necrosis, and decreased yields. This study examined the effectiveness of hot-water treatment for controlling P. penetrans in P. frutescens under large-scale conditions at two different temperatures and durations. Additionally, because ornamental plants are often a main route for the international spread of quarantine plant-parasitic nematodes, two commonly traded ornamental species (Syngonium podophyllum L. and Schefflera arboricola L.) were examined alongside P. frutescens to assess how hot water treatment affected their health by measuring weight, chlorophyll content, and root length. Results indicated that the relative reduction in P. penetrans recovery was 99.66% at 48 °C for 20 min and 99.98% at 50 °C for 3 min. While some thermal damage was observed in P. frutescens following both treatments, exposing the plants to 50 °C for 3 min did not significantly affect the quality of S. podophyllum and S. arboricola. These results highlight that hot water treatment effectively controls plant-parasitic nematodes and maintains ornamental plant quality, which could aid in developing quarantine protocols for traded planting materials.