21 November 1997

EU proposals not strong enough to stop brown rot

By Allan Wright

PROPOSED EU control measures against potato rot are not strong enough, the annual conference of VTSC growers in Aviemore was told last week.

The EU brown rot directive does not include tomatoes, does not prohibit irrigation with surface waters, allows joint use of machinery, and permits farmers to produce both ware and seed potatoes on the same unit, said Eric Faldo, technical director with Danish seed exporter Danespo.

"Our experience in controlling ring rot, with no cases in seed crops since 1992, suggests stricter controls than those proposed will be needed to eliminate brown rot from Europe. We would suggest that the measures we took to prohibit surface water irrigation, sharing of machinery, and non-specialist seed growing should be included in the regime."

"We also know from experience that it is not so much legislation and inspection which eliminates a disease, but correct management and handling by producers," he added.

Dr Faldo said Finland, Germany, Spain and Sweden were most at risk from ring rot with Holland, followed by Portugal, Spain, Italy, and Belgium most at risk from brown rot.

He also warned that other diseases like powdery scab, necrotic ringspot, root knot nematodes, potato cyst nematodes, pink spot, and late blight were threatening Europes seed potato industry.

"European multiplication and control systems do not seem to have been able to restrain the spread of pests and diseases and may have introduced new problems. "We have placed too much faith in multiplication from tissue culture and mini tubers."

Variety mixtures in mini tubers from different countries, more deviating types within deliveries from a single country and infections from mini tubers, believed to be indexed and disease free have all been seen. "We have had virus Y infection and mop top infection from a well-known European mini tuber laboratory and we have forced a Danish state laboratory to stop mini tuber production because of mop top problems," he said.

He urged seed producers to revert to clonal selection and place more emphasis on trueness to type, as well as strengthening the EU brown rot directive.

EU brown rot measures need to be far more stringent to eliminate the disease, Denmarks Eric Faldo told Scottish seed growers.