Rhizomania in fodder beet is becoming a problem for livestock farmers in the UK. The disease can reduce root yields by as much as 70%, but despite this, some fodder beet growers still continue to plant susceptible varieties in rhizomania-affected areas of the country. Growers can help reduce the build-up and distribution of the disease and protect their yields by growing a rhizomania-resistant variety such as Ribondo, says Martin Titley of seed breeder Limagrain.
Rhizomania is a soil borne disease caused by the beet necrotic yellow vein virus which is spread between plants by a root parasite. There is no treatment for the virus which reduces root yields in sugar beet and fodder beet, and the resting spores of the virus vector can remain dormant in the soil for decades. The worst affected areas are in East Anglia, Lincolnshire and the Midlands.
Dr. Mark Stevens from the British Beet Research Organisation explains: The only real method of combating rhizomania is through varieties with resistance against the virus, hence the requirement for fodder beet growers to also plant rhizomania-resistant varieties. All sugar beet varieties on the 2013 NIAB list are partially resistant to rhizomania, however the same cant be said for fodder beet varieties. Initially, when the disease is present at low levels, it is quite possible for the disease to exist within the soil but for growers to be unaware of it.
By planting resistant varieties of fodder beet and sugar beet, growers can help fight the challenges of the disease. When selecting a variety, rhizomania-resistance should be one of the first things to look for to maximise yields for the future and prevent the build-up of the disease.
The wet weather weve had hasnt helped the matter as rhizomania likes warm, moist soil. Plus, when mud from rhizomania-infected fields sticks to machinery it is transported from field to field and farm to farm, furthering the spread of the disease.
Mr Titley elaborates: Livestock farmers in disease-prone areas should be growing rhizomania-resistant varieties which reduce the build-up and distribution of the virus, and therefore prevent reductions in yields. Selecting a fodder beet variety such as Ribondo, which has been specifically bred to be rhizomania-resistant, is ideal for the job.
Rhizomania can be transferred by farm machinery, grazing livestock and the footwear of those who visit rhizomania-infected fields. The virus can also survive in the dung of cattle which have eaten infected beet. As its such an easily transmittable disease, livestock farmers should ensure they plant resistant fodder beet varieties to safeguard their yields and reduce the chance of spreading the disease in rhizomania hot spots.
Good farm hygiene plays a key role in the control of the spread of this disease. Measures should be taken to reduce soil movement between fields and farms, in particular, contractors with machinery. Ensuring a longer rotation of fodder beet will also help keep disease levels low.
Dr. Stevens sums it up: In disease hot spots, the only way rhizomania can be controlled is by growing resistant varieties of fodder beet and sugar beet, and by practicing good farm hygiene.