Virulence and pathogenicity of four Ditylenchus dipsaci populations on sugar beet

The stem nematode, Ditylenchus dipsaci, is a severe pest in European sugar beet production. In France, Germany, and Switzerland, D. dipsaci damage in sugar beet varies among specific geographic areas. In this study, the reproduction potential of four geographically distinct D. dipsaci populations was determined using sterile carrot disc cultures. In addition, virulence and pathogenicity were investigated in-vivo using sugar beet. No difference was found in the reproduction potential on carrot discs, as well as penetration rate in sugar beet seedlings. The reproduction rate in sugar beet tissue was significantly affected by the D. dipsaci population used. The population from Seeland (CH) showed the highest number of nematodes per plant at 60 dpi (21,071.8 +/- 5340.0), compared to the three other populations contained 3588.6 +/- 3858.3, 5136.9 +/- 4950.8, and 3579.7 +/- 5174.2, respectively. Furthermore, the reproduction rate of D. dipsaci was negatively correlated with fresh biomass of sugar beets at 60 dpi. Based on these results, the D. dipsaci population Seeland is suitable for breeding programs to detect resistance in sugar beet. After selecting candidate genotypes/varieties, these should be further evaluated for their field resistance in their targeted growing regions.

Automated summary

In European sugar beet production, different populations of Ditylenchus dipsaci show varying levels of damage, with the Seeland population having the highest reproduction rate on sugar beets. The reproduction rate of D. dipsaci at 60 dpi is negatively correlated with the fresh biomass of sugar beets. These findings can guide breeding programs for sugar beets resistance.