After about 3 weeks of growth, the squash in our spring garden, started getting a powdery mildew infection. In the picture above, there is a health young squash on the left. The young squash plant on the right is starting to develop Powdery Mildew. The first signs I usually see, are the small white spots on the leaves (visible on the squash to the right). You can also see the affected leaves turning yellow around the edges. If this infected squash were left untreated, the leaves would all yellow and the plant would die in around 3 weeks or so.
Here is Jacksonville Beach, the powdery mildew has been particulary bad, and a constant problem, on all our cucurbits. I was able to save several of our squash plants, but a few withered and died. I use a solution of milk and water to treat the Powdery Mildew. I mix a quarter cup of milk in about half a liter of water, and apply with a spray bottle. I try to coat the leaves on both sides with the milk solution. It works pretty well. I usually takes about 3 or 4 days of spraying everyday to get rid of the powdery mildew if you catch it early enough. I have found that if you start treating the plants with milk after some of the leaves are yellowed and brown, it may be too late. I also try to remove any infected leaves from the plants, to try and prevent spreading. I'll post another article soon with more details on powdery mildew treatments.