Can one use sodium bicarb?
Powdery Mildew on Crepe Myrtle
Yes you can, however their is a product on the market called Green Cure that is hands down the best product I have seen for powdery mildew knock down and control. It will do so without having some of the foliage burning potential that sodium bicarb does. Potassium bicarb is actually one of its main ingredients and Green Cure is an Earth Friendly product. Link: http://greencure.net/
I have used this product for many years now and it has done a fantastic job in my gardens and rose beds.