9 June 1995

Fingers crossed over relaxed rhizo rules…

Policies to limit the spread of rhizomania in the UK sugar beet crop were relaxed last year. Was it a sensible move? Robert Harris reports

RHIZOMANIA was first found in the UK eight years ago. But the feared epidemic has not materialised.

Ministry containment policy has played a big part in that, says Mike Asher, disease specialist at IACR-Brooms Barn research station, Suffolk.

But that policy has been relaxed, after a MAFF/industry review last December. Crop surveys will be less intensive, and on-farm restrictions have been eased. Dr Asher believes most changes are sensible, but some concern him.

National crop surveys are largely unchanged. He welcomes that because aerial surveys help pinpoint new outbreaks. Some 200 fields a year are identified as suspicious, of which two or three are usually confirmed as infected.

Random field inspections, and of farms linked in some way to existing outbreaks, for example, those sharing contractors, remain.

No automatic inspection

But beet grown within 3km (0.65 miles) of an outbreak will no longer be inspected automatically, says Dr Asher. "I am slightly worried that they might relax this too much. Most new outbreaks have been found by this method."

That is because, as with all soil-borne diseases, outbreaks tend to occur in clusters, he explains. "The aim of containment is to prevent infected beet being knowingly delivered to factories. To do that seriously, you have to look where the disease is most likely to occur."

Affected growers will suffer less under the new policy, he says. Previously all the crop in an infected field was destroyed. Now the ministry will mark infected areas for destruction, allowing the rest to be harvested.

Cropping on infected fields has been "relaxed enormously", he adds. Anything, except beet or transplanted crops like seed potatoes, can now be grown. Previously, this could only be done on lightly-infected fields – those with one isolated disease patch. Most had more than that, and had to be grassed down or direct-drilled with cereals.

"I think these changes are sensible. The policy was very restrictive and a major stumbling block. Farmers can now grow ware potatoes, parsnips and carrots, so it is not hitting businesses as hard."

Soil waste concern

Dr Ashers main concern is soil waste. Crops removed from such fields are still subject to a "1% additional soil" limit. In the past this had to be disposed of in a MAFF-approved tip by licensed processors. Now this will take place under a voluntary code of practice. "We need to be clear that this is monitored closely enough," says Dr Asher.


&#8226 Surveys largely unchanged.

&#8226 Automatic inspections within

3km of outbreaks dropped.

&#8226 Partial rather than whole

crop destruction.

&#8226 Cropping restrictions eased.

&#8226 Code of practice for soil

disposal introduced.

The rhizo rules may have been relaxed but precautions, like disinfecting boots after inspecting suspect fields, lessen the chances of disease spread.