SePRO Camelot O is not labeled to treat Rhizosphaera. We would recommend using Docket DF as it is one of the most popular products for Rhizosphaera Needlecast on Blue Spruce Trees. You will need to use 5 lbs of Docket DF per 100 gallons of water (1.25 lbs of Docket DF per 25 gallons of water) for Rhizosphaera Needlecast on spruce trees.
SePRO Camelot O would be a good product to use and is one of the few we carry that is labeled for needle blight.