alder leaf disease
We have a hedge of about 30 alders which were cut with an electric hedge-cutter about a month ago. Noticed, a week or so ago, that many of the leaves are curling and have, mostly either side of the spine, rows of 'pimples', each 3-5 mm in diameter. They seem to start being pale green with small brown spots, then the middle of each spot cracks into a hole.
Will be grateful for diagnosis & treatment.