Just when you think you’re going to have a bumper crop of cucumbers and zucchini, the attack comes. First the leaves turn a dull gray, then almost white, and then the leaf shrivels and dies.
Powdery mildew is a fungus that it attacks plants usually at the end of growing season. Some gardeners say to take powdery mildew lightly. I’ve seen it destroy the whole crop of cucumber and zucchini. The leaves are the source of sunlight, and the plant needs sunlight to live. Powdery mildew kills the leaves, and if all the leaves die, so does the plant.
Luckily there is a very simple fix — not a cure — a fix. Apparently, there is no cure. However, Simply spraying the leaves with a mixture of baking soda and water will keep powdery mildew under control.
The first step is to cut off any leaes that are damaged beyond repair. Put these leaves in the garbage. Do not compost them.
For the remaining leaves, spray with a mixture of baking soda and water.
Try to do this when the plant is not in direct sunlight. Early evening is the best time.