Depends on what's wrong with it

Can you post photos?

Just did.

I am not an arborist but it looks like there might have been a root that girdled the base of trunk, caused some bark problems followed by insect invasion and possibly some other disease. Not sure it can be saved. A good arborist can evaluate and give you professional recommendations.

any recollection of what it was sprayed for???

Unfortunately no.

The bulge at the base is most likely a burl, which willows are prone to. While burls are abnormal growths, they occur with many trees and have not been found to be detrimental to tree health.

OTOH, willows, Salix species, are prone to a vast number of insect and disease problems and are known to have a relatively short lifespan.

With a tree having that depleted an appearance, I'd say its days are numbered. I'd think seriously about removal and replacement.

Looks like the burl has grow mostly or entirely around the base, gradually girdling the tree. No way to help it.

Base looks like there is decay = tree may topple soon

I think we have consensus here. Time to remove and plant new tree in different spot.

Thank you for all your comments We’ll take it down and perhaps plant a new and different tree.