Looks like Rich does not log in daily. I Googled "liquid zinc for trees" and got several hits. Mostly they talk about pecan trees. Here's a link that might help.

The article says you can also make a 'zinc tea' with zinc sulfate.

Good luck ernie.

Here is a link that might be useful: Liquid Zinc Nitrate

Thanks Mary!
I was using the wrong search words.
I found zinc sulfate powder, but no instructions on use. The company didn't even write back!
Now I can help my tree.