Soil-borne cereal mosaic virus (the disease formerly known as Soil-borne wheat mosaic virus)
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This disease was first identified in the UK in 1999. As with other soil-borne diseases, the finding of symptoms in a crop suggests that the causative organisms have been present for several years and are likely to be much more widespread. Indeed, in recent years there have been many more outbreaks over a wide area. The section below entitled ‘Soil-borne cereal mosaic virus (SBCMV) – biology and control’ gives some background information on this disease. |
Consultation with the Cereals Committee of the National Farmers’ Union
in 2001 and 2003 showed that the industry wished to avoid the imposition
of stringent control measures on affected growers. On this basis it would
not be appropriate to pursue listing of the disease in the EC’s
Plant Health Directive. Given the presence of the disease in other
EC member states the only realistic option for listing would have been
to seek protected zone status. If this had been achieved, drastic action
against affected growers, similar to those which applied in the early
outbreaks of the beet disease known as Rhizomania, would have been
necessary to maintain that status.
There is a range of wheat varieties tolerant to the disease and this
gives cereal growers the means to take action where the disease is
found. A LINK research project, entitled “Controlling Soil-borne wheat
mosaic virus in the UK by developing resistant wheat cultivars”
(details accessible
here) comes to an end in September 2006.
Whilst policy on this disease was being considered, affected farms
were placed under statutory notice to take hygiene measures to restrict
further spread of the disease. These notices have been lifted and growers
are advised to practice good agricultural practice, in particular by
preventing the spread of soil from arable fields, to limit the
risk of the further spread of this disease. A guidance sheet on the
risks from soil movement is attached here (please
note that this was prepared using the old name of this disease).
Soil-borne cereal mosaic virus (SBCMV) – biology and control
SBCMV is very similar in terms of its biology and the symptoms it produces on winter wheat to barley yellow mosaic virus, a common disease of winter barley in the UK. Foliar symptoms are most prominent in early spring when yellow patches become evident in the crop. Plants are stunted with prominent yellow streaks on leaves and leaf sheaths. Yield losses of 50% have been recorded in the patches on susceptible winter wheat varieties. Both viruses are spread by Polymyxa graminis, a soil-living organism and SBCMV can survive in the resting spores of Polymyxa for at least 25 years. The main method of spread is via the movement of infested soil on vehicles and machinery or in soil attached to transplanted crops such as seed potatoes.
The most effective control is to avoid introducing this disease by adopting suitable hygiene measures on the farm. Taking a few precautions can markedly reduce the risk of introducing these and other pests and diseases onto your farm.
- Ensure all visiting contractors or shared machinery is as free
of soil as possible
- Dispose of waste soil and vegetable matter from cleaner-loaders,
potato riddles, etc. to an on-farm tip or return to the field of origin
- Do not feed or spread untreated waste from imported vegetables
- Be aware of the risks of planting seed potatoes produced in areas
of continental Europe where SBCMV and other soil-borne viruses are
known to occur
- Be wary of bringing animal slurry or manure onto the farm
- Never purchase small ware potatoes, you may plant more than you bargained for!
Once land is infected, the only practical means of control is to grow
partially resistant varieties. These varieties yield very well in infected
sites and the level of inoculum build-up in the soil is much lower than
when susceptible varieties are grown.
Resistant varieties on the current recommended list are:
Claire
Cordiale
Hereward
Xi19
Other varieties shown to be resistant in experimental trials are:
Aardvark
Andromeda
Cadenza
Charger
Cockpit
Exsept
Goodwood
Heritage
Moulin
Phlebas
Rampart
Scorpion25
Virtuose
Woburn
The above results are based on data collected from large
plots and/or tussock plots by CSL and NIAB. For additional information
please contact Giles Budge (g.budge@csl.gov.uk)
or Rosemary Bayles (rosemary.bayles@niab.com).
Page last modified:
22 Nov 2006
Page published: 16 Feb 2006