It looks like anthracnose. Cool, rainy weather promotes it -- heat eventually stops it, but not before damage is done.

There isn't much you can do except apply a fungicide, but that needs to be done before the damage occurs.

That's happening here too. About 2/3 of the flower/bract buds never opened and just fell off. The flowers/bracts that did open were heavily deformed, which splotches on the bracts and leaves.

What is the best fungicide folks??

very likely anthracnose - but you might want to check in with local college/arboretum folks, as I found out a few years ago that my dogwood had anthracnose, but not the fatal kind.

I trimmed off the affected leaves/shoots, and the plant put on new growth within a month or so as if nothing had happened.