Disease Threat to Conker Trees

10.58.00pm BST (GMT +0100) Tue 18th Sep 2007

Twin blights of pests and disease are threatening the health of horse chestnut trees in Milton Keynes, causing a potential 'conker shortage'.

Leaf miner insects and bleeding canker disease have come across from Europe over the past five years and could pose as big a threat to the trees' survival as when 20 million elms were lost to dutch elm disease during the 1960s.

Leaf miners attack the foliage of the trees, stripping off greenery and leaving them unsightly and unable to produce conkers, while the disease known as bleeding canker causes the trees to become brittle and unsafe.

To meet this challenge, Milton Keynes Council's tree expert is identifying infected trees and deciding whether they need to be felled for safety reasons.

In Milton Keynes, the Council is responsible for caring for more than 110,000 trees within 806,000 square metres of woodland. Up to 15 per cent are horse chestnuts and nearly all are showing signs of infection. One of the worst hit areas from bleeding canker is the Coffee Hall grid square.

When trees become diseased, there is sometimes no alternative but to remove them on safety grounds. Unfortunately nearly all horse chestnuts in Milton Keynes are showing signs of the disease, which looks like black treacle coming out of the bark. Sometimes they are able to heal themselves and recover from the disease, so the Council is monitoring them. They will only be removed as a last resort, and they will be replaced.

Liberal Democrat councillor Douglas McCall, cabinet member responsible for the environment, said: "Trees can invoke highly passionate responses even when, as part of our maintenance programme, we have to remove some that have become dangerous.

"But for the overall health of the thousands of trees in Milton Keynes, it is important to have an effective maintenance and replacement scheme. That is why I am pleased to say that, last year, we planted thousands more trees in Milton Keynes to make the city a better and greener place to live as it grows."