| Jim. Crape myrtle flowers don't have balls, they have stamens. ;-) Anyway, those little balls are the seed capsules that form after the blooms are all finished being pollinated. I would assume that you have an infestation of powdery mildew, though I can't make an absolute diagnosis without an image. If you do have a mild case of powdery mildew, I have found that applications of horticultural oil (summer weight) can be very helpful. Some people report success with baking soda solutions as well, but I can't speak to that. Do some searches (google) on powdery mildew and you will find some important cultural activities to help you prevent another outbreak next year. Do you know what Crape Myrtle cultivar you have? Some are exceedingly resistant to this common disease while others will become infested routinely. | 
