Rhizosphaera Needle Cast on Blue Spruces
 

Hi all. Newbie of sorts here. I live in an area with several blue spruces
in my yard. I've determined that they have Rhizospahera Needle Cast, per an
Adobe file found on the internet.

My question is this: There was a suggestion made to use copper sulfate and
hydrated lime, along with water, and spray this on the trees every Spring.
I have respiratory problems and am especially concerned about the copper
sulfate. Can anyone suggest a less toxic fungicide for this problem?
Would sulfur work? Thank you.