31 July 1998

Brown rot control

ABSTRACTION from any watercourse known to be carrying potato brown rot bacteria could be banned under new legislation agreed in Brussels.

The Brown Rot Control Directive comes into force in July 1999 and will supersede existing UK legislation. One of the rules will restrict the use of water for irrigation from infected watercourses.

"The question is, what does infected actually mean?" asks Mike Storey of the British Potato Council. "It still has to be defined and is open to some interpretation." The danger is that any level of infectivity may count under the terms of the directive.

That would be a particular problem to potato growers in the Great Ouse catchment area in Beds and Cambs. The pathogen has been found in nightshade plants on the riverbank and is thought to be behind a local outbreak of bacterial wilt in tomato plants last year.

But the release of bacteria into the watercourse is determined by several things, including the age of the plants and water temperature. As such, irrigation is not banned automatically under UK law. That could change with the Brussels directive.

Generally, however, the new law has been welcomed. "It provides us with the EU-wide controls we have been looking for," says Dr Storey.

In addition to the restrictions on watercourses, the directive requires all member states to carry out systematic surveys for brown rot and follow specific eradication procedures when it is found.