In response to David J Wilde (What’s wrong with Knavesmire chestnuts?, Letters, September 9) the premature wilting of horse chestnut leaves is the result of the activity of a leaf miner bug that has spread north from Europe.

I understand there is little we can do to eradicate this species specific pest at the moment. There also a horse chestnut die back disease that is not pest-based in the offing but it has yet to arrive here.

J A Whitmore, Orchard Paddock, Haxby