What To Do About Powdery Mildew
Powdery mildew is a common sight on many summer crops. Powdery mildew can often be unsightly, but it’s typically not the actual cause of significant yield reduction. Nearly all squash and tomato plants will experience some amount of mildew and its normal for older leaves to wither and die.
Healthy plants grown with rich compost and adequate water will suffer far less than plants in poor soil with over or under watering.
From our experience, milk sprays (sometimes recommended online) are ineffective.
If a plant is producing well and new growth looks healthy, leave it alone (you can pull off mildew covered leaves if you want).
Check soil moisture and provide a liquid fish emulsion, or pull the plant all together and prep your soil for a good fall crop.