Gypsophila paniculata root saponins as an environmentally safe treatment against two nematodes, natural vectors of grapevine fanleaf degeneration.
Background and Aims: Xiphinema index and X. diversicaudatum are nematodes that transmit the grapevine fanleaf virus and the Arabis mosaic virus, respectively. These viruses are the two agents mainly responsible for the disease that causes the most economic damage to grapevines worldwide. The infectious degeneration of grapevines affects vine performance and grape composition. The control of Xiphinema populations by soil disinfection is now impossible because of the removal from the market of the last available chemical treatments. In this study, saponins are assessed as an alternative treatment to control nematode populations. Methods and Results: The nematicidal effect of saponins from Gypsophila paniculata roots was tested against X. index and X. diversicaudatum. In aqueous media, a concentration of 1 mg/mL was associated with a mortality of greater than 95% in both nematodes, while in rearing soil, 73% of X. index and 85% of X. diversicaudatum were killed by 150 µg of saponins per gram of soil. In addition, an ecotoxicological study was undertaken on two soil bio-indicators (the mycorrhizal fungus Glomus mosseae and soil nitrification) that revealed that they were not affected by Gy. paniculata saponins at a nematicidal concentration. In the soil, investigation of the major Gy. paniculata root saponins revealed that these molecules were completely degraded in the soil within 4 days. Conclusion: We show that Gy. paniculata saponins are an efficient and environmentally friendly treatment against two nematodes that transmit grapevine fanleaf virus. Significance of the Study: This saponin-based alternative to chemical treatments could provide an environmentally safe and efficient solution for vine growers to use against grapevine fanleaf vector nematodes.