Dear Group

I have both an old pear tree and young plant that appear to have the same
problem.

The outer edge of the leaf develops a black line all around it (say 3mm to
5mm thick). This happens to all the leaves on the old tree, but also appears
on good a number of the leaves on the young plant early in the season
(spring). The leaves stay on the trees until autumn, but the trees are not
very productive at all.

The soil has ph of 6.5 and there is quite a high rainfall and the location
can be windy at times. The soil is quite well drained and the plants receive
full sun in the late spring summer.

Any ideas what the problem may be?

Thanks
Iain