Efforts to eradicate a virulent plant disease from Cannock Chase could prove useless if the infection has reached the roots.

Infected bilberry bushes have only been cut and burned down to their roots, meaning the plant could grow back and still be infected.

Staffordshire County Council has identified a 2,250-acre containment zone within the 3,000-acre Cannock Chase country park which has areas of infection.

The council has no idea if the infection is in the root system but, if that was the case, the current process of removing infected plants would still have stopped the spread of the disease and bought the council more time to research a way of killing it for good.

In January, the council was forced to close off sections of the Chase to walkers after discovering a never-seen-before strain of phytophthora spores which could decimate the plants.

Government scientists and plant experts have praised the way Staffordshire Council has handled the crisis.

The experts have backed the call from Staffordshire County Council to dog walkers and other Chase users to stick to the main paths and keep dogs on leads, to avoid spreading the disease further.

Council head of environment Steve Potter said : “This is the first time the disease has been identified in bilberry so we are in uncharted territory.

“Complete destruction of the root system would not only be enormously expensive and time consuming, but it could well be counterproductive, removing from the Chase the very habitat we are seeking to protect.”