copper is toxic, so exposing on the buds/blossoms which bees will interact with would be detrimental to their health.

Why would the instructions say to spray during full bloom then?

I would not do so. And perhaps inquire with Bonides help line or online support. I just looked at my Southern Ag Copper fungicide doc and it explicitly says not to spray during full bloom. But if you google copper toxicity and bees, you'll find the science documentation regarding that.

Without seeing or being able to read the label instructions, it's difficult to know why this was stated. But it is a well accepted horticultural convention that you never spray any pesticide when pollinators are present, even so-called natural ones. Typically, you can safely spray upto the pink bud stage and after petal fall, never in blossom.

Thanks, guys. It didnt sound right to me which is why I asked. Guess I will just wait until the petals fall off and hopefully that will help with the brown rot. I already sprayed once before the buds opened.