These brown/black spots have appeared on a single branch of a young lemon tree - other branches are unaffected. Any advice much appreciated, thanks!
I am not sure what is causing these brown patches, it looks fungal. My best advice would be to prune the infected branch and destroy before it starts to infect the rest of the tree. Once you have removed the diseased branch I would spray the tree with a broadspectrum fungicide like Yates Copper.