Thermal Treatment Technologies Impede Hatching and Inhibit Reproduction of Potato Cyst Nematodes (Globodera spp.) in Infested Soils

The spread of potato cyst nematodes (Globodera pallida and Globodera rostochiensis) via residual soils endangers the cultivation of potatoes. The aim of the study was to investigate the effectiveness of thermal treatments against potato cyst nematodes (PCN) as part of reliable routine phytosanitary measures in processing plants accompanied with the highest possible throughput of tare soil. The viability and reproduction rates of potato cyst nematodes embedded in gauze sachets in a residual soil matrix were tested after treatment with dry heat, hot steam, or microwaves. An 80 degrees C heating by microwaves in a magnetron tunnel, which was reached after 2-7 min, was found to inactivate the potato cyst nematodes after 15 s of exposure. The data indicate that conductive heating in the Sterilo effectively kills cysts in soils when heated to 68 degrees C and allowed to cool down for 16 h. Inactivation of cysts was also found, when hot steam treatment (adjusted to 80 degrees C) was applied for 5-6 h, followed by a cooling phase for at least 18 h. We conclude that PCN's viability and the ability to reproduce on susceptible potato plants is eliminated after thermal treatment at 80 degrees C with microwaves as the most effective measure with the lowest energy effort.