My zucchini has powdery mildew, as it does every year (new location this year). In the past, I’ve just ignored it, but I wonder if there’s anything I can spray it with to prolong the life of the plant and get the most zukes possible (crazy, I know!)
It is too late to try this year, but if you can spray the leaves with baking soda BEFORE the powdery mildew usually appears, than it will change the pH of the leaf surface, preventing the powdery mildew from growing there. You would need to reapply after rain and watering. As far as I know, the baking soda won’t make a difference, if you can already see white.