I have a customer who has a Blue Spruce that the new growth is turning a purplish/brown color. Not all the new growth, just some of it, and it is scattered in no real pattern around the 7' tall tree. It looks similiar to Rhizosphaera needle cast, but it is the new growth not older and all over the tree. They have two other spruces that have NO damage. No evidence of mites either. All three trees were treated with bifenthrin about 5 weeks ago. I can't find any sensitivity issues with spruces and bifenthrin. I am leaning towards a sensitivity issue since nothing else seems to fit. any thoughts??