When I was a little kid my mom made me a "playhouse" by planting a circle of sunflowers and planting morning glories all around them.
The morning glories covered the sides and made a drapey kind of roof over all. /powdery mildew means they're not getting enough water.
I remember this from the first year I grew sunflowers.
I grow them as a living fence to block my nosy neighbors from hanging over the waist high fence and gawking at my every move. Anyway, I've been doing it for quite a few years now and the bees no longer bother me. I even dead head them while the bees are on the other blooms.
They really, really do not want to bother you and all you have to do is start slowly walking away if some bother you. The last thing they want to do is sting you so if you don't move suddenly or act aggressively, you have nothing to worry about.
The will mind their own bees wax.