I came across an interesting article today on an environmentally friendly way to protect your squash from getting mildewy leaves.
Numerous small studies from around the world have validated the use of milk sprays on powdery mildew on a wide range of plants. Most recently, a spray made of 40% milk and 60% water was as effective as chemical fungicides in managing powdery mildew of pumpkins and cucumbers.
Scientists are not exactly sure how milk sprays work, but most think proteins in the milk interact with sun to create a brief antiseptic effect. Any fungi present are "burned" into oblivion, but there is no residual effect after that. In order to be effective, milk sprays must be used preventively, must be applied in bright light, and should be repeated every 10 days or so.
There is no consensus on which dilution of milk to water is best, with the most concentrated recommended mixture 40% milk and 60% water, and the most dilute 10% milk and 90% water. I fall in between using 30% milk to70% water, with good results. It does not matter if the milk you use is skim or whole because it is the protein rather than the milkfat that is working on your behalf.
With experience, you will learn which types of powdery mildew are likely to develop in your garden, and this knowledge will take you far in managing this disease. Like other fungicides, milk sprays work best when used preventatively, before the disease can gain a foothold. If you often see powdery mildew on your squash, grapes or zinnias, start milk sprays before the plants show signs of infection. You have nothing to lose beyond a cup of milk.
For more information, visit
growveg.com