No disease that I know of. I have two of these in my garden and I regularly cut them back very hard. They always respond and come back even more vigorously. The only problem that I have encountered is that they seem to attract black fly.

according to a mate of mine who helps at the Yorkshire arboretum if they sit in wet for prolonged periods they can drop branches.
so after the wet winters that could be the cause. generally pest free.

I think we all sat in wet this winter past..I didn't know they hated wet - but the bank it's on is pretty dry and sandy - but nowhere was dry last winter was it?
I do cut the Black Lace back quite hard but have never cut the wild one. Will give it a try when the flowers have finished. But it doesn't look very well to me. The sparrows would miss it - its their "private" tree I think. Strange how the whole tribe lives in that corner of the garden and don't normally spend much time anywhere else.

Thank you for the suggestions, and fingers crossed!

Interesting question this, mainly because Stera says she has ONE self-sown Elder! We have hundreds - literally - wherever the birds roost in the trees there are Elders growing underneath! I have never known any disease with these wild ones, I can't grow the Golden one, it doesn't like my clay soil, but the wild ones are everywhere. They grow quick too, if you cut them to the ground they will spring up again, not easy to dispose of, which is not the problem here. We have several which are now trees and not bushes and they get hacked as necessary, but do have loads of dead branches, so I wouldn't worry, just cut them out.

Thank you everyone.

Jimmy black fly don't see to have noticed it - too keen eating other things ...

Lol,Honey, don't wish any more seedlings on me - I have more than I can cope with with the Ash ones! I 'haven't seen any other elders in the near neighbourhood but that doesn't mean there aren't any - this one seeded from somewhere..
My only bit of half superstition is to apologise to the tree if I cut a branch off, but must have offended it somehow anyway, lol.. I'm not sure when one stops being a bush and starts being a tree - ours is about 12' and is tree shaped.

It did have some Jews Ear fungus on it a few years ago if that's any clue. Might try cutting it to the ground then and see what happens. I can always use the Black lace for tea after all - the berries on that are miserable small things and no loss. But you're right about the wood being difficult to dispose of. Hard to cut and hard to burn (though we are not allowed fires at present)

I didn't specially want it in the first place but have sort of got used to it being there...don't like to see things dying, there's enough of that round here with the poor ash trees.