Hello,
I hope you can help or advise.

We have a well established elderberry tree at the back of our garden that is
at least 20-30 years old, standing alone. We have lived in this property
for 3 years but I grew up, as a child with, elderberry trees and have never
seen one so infested with blackfly (and ants!). In previous years here it
has been fine.

We noticed today that the leaves have started to wilt and drop off. This is
happening to about half of the tree. The flower buds don't seem to yet have
been affected (although are infested) I suspect it is a matter of time
before they go the same way.

Is there anything I can do to halt the infestation. I am reluctant to use
chemicals as we are organic - but for the sake of the tree, I will try
anything! Will it die? or just have a really bad year? Should I leave it
and let it try to survive?

Thank you in advance for your replies.

Cheers
Pippa