Assessment of the nematicidal potential of vermicompost, vermicompost tea, and urea application on the potato-cyst nematodes Globodera rostochiensis and Globodera pallida

The addition of organic material to the soil can be an effective alternative to the environmentally unsafe chemical treatments that are used to control plant parasitic nematodes. We evaluated the effects of vermicompost alone, and aqueous solutions of vermicompost (vermicompost tea) either alone or mixed with urea, on the development and survival of two potato-cyst nematodes: Globodera rostochiensis (pathotype Ro1) and G. pallida (pathotype Pa2) and on the growth parameters of the host potato plants. Soil amendments with these materials significantly decreased the number of cysts · 400 g–1 of both species in the soil, the number of eggs and juveniles · cyst–1 of both species, and the number of eggs and juveniles · g–1 of both species in the soil, relative to the untreated controls. The suppressive effect was significantly higher at the highest dose than the lowest treatment dose, for all tested materials. Globodera rostochiensis was more sensitive to all the tested materials than G. pallida. The aqueous solutions of vermicompost alone or in combination with urea were more effective than the solid vermicompost used alone, for controlling both species. Vermicompost and the vermicompost teas had positive effects on plant fresh stem weight and stem height. The application of vermicompost tea instead of the solid vermicompost, substantially decreased the amount of material needed. These amendments are thus promising for the control of potato-cyst nematodes in sustainable agricultural systems.