No authorized chemical treatments for Rhizomania exist. The only effective way to control it is by using a seed variety with resistant genetics. Resistant varieties help to inhibit the spread of the virus across the field.
Over the past two decades, plant breeding has led to remarkable advances in the development of Rhizomania-resistant varieties. Today, resistant varieties are as productive as conventional varieties. In addition to using Rhizomania-resistant varieties, a number of agronomic measures are recommended:
- Reduce humidity in the soil through sufficient drainage, maintenance/improvement of the soil structure, sparse irrigation limited to as much as 70% of the sugar beet crop’s requirements.
- Avoid soil movement. Harvest in dry conditions.
- Plant early.
Extending rotation is advised but will only have a limited effect on the infectious potential due to the durability of the Polymyxa betae/BNYVV complex — it can remain dormant for decades.
Resistant Gene Management
To date, the ‘Holly’ gene serves as the main source of resistance. This dominant gene makes the work of plant breeders easier. However, there is concern that new strains of the virus will overtake the dominant gene. Viral evolution such as this is well documented.
These new strains are beginning to cause serious outbreaks in California, southern Minnesota and Idaho due to the strain’s aggressive mutations and the areas’ favorable growing conditions.
To counteract this risk, Seedex has partnered with SESVanderHave to provide better Rhizomania-resistant varieties based on Tandem Technology. This genetic technology provides two sources of genetic resistance. It pairs a new source of resistance proprietary to SESVanderHave with the Holly gene (the resistant source that all US sugarbeet seed companies currently use). Tandem Technology provides unparalleled resistance even under extreme Rhizomania pressure.