Weeping Willow troubles

[rachjj25]

Weeping for my willow

I am hoping that someone can offer me some advise about my poor tree. We planted our lovely weeping willow tree in our backyard about four years ago and it has grown taller than our two story house. I became concerned two years ago when these holes started developing around the trunk near the base. The largest hole is about 8-10" in diameter and the bark has sort of raised around the rims of the holes-they look a little like cankers. Also, I was poking around in the hole and there were earthworms living in there.
Then the leaves started turning brown and falling off in abundance.
I hired a tree service to come and look at it and the lady (not an arborist) said that cankers were normal for weeping willow trees but that the tree had some some of disease and she recommended taking it out. I figured that she offered that advise because the tree service would make more money removing the tree than treating it.
I then took some of the damaged leaves to a local nursery and they said that the tree was infected with rust, which I promptly treated with Isotox and the tree seemed to get better.
Early this spring, I was pruning back some of the branches and noticed a lot of small dead black branches. Then, the rust came back. I have treated the tree twice this year already with a spray treatment however, the tree is dropping a lot of leaves and just doesn't look healthy.
In hindsite, I realize that I should have not planted a weeping willow in my backyard considering the size that these trees grow to and the relatively small size of this lot, but the tree has provided us such wonderful shade from these hot Sacramento summers.
Any recommendations? Is it true that canker looking holes are normal on a willow? :help:

 

[Kneejerk Bombas]

Those look like burls, which are common on Willows and shouldn't concern you.
Also common are many different types of leaf disorders, chewing insects, dead twigs and even larger limbs that get shaded out by the upper canopy and die.
Rust is a fungus, Isotox is an insecticide. So unless your insects have fungus, you're not doing much.
Do yourself (and all of us a favor) and stop buying useless chemicals. Take what you have left to a recycle center and dispose of any application equipment you may have.
The chemicals available to homeowners can be stronger and more dangerous than those commercial user get, plus, homeowners don't have a clue how to properly use them in many cases.
If you want to help your willow, water it, they love water. you might want to find an ISA Certified Arborist to do some light trimming to remove the deadwood and possibly start training the top to grow away from the buildings. This would be done with cuts smaller than 3 or 4 inches, not huge cuts that would leave huge scars.