By Mattathove
United Kingdom 
My courgette plants are becoming covered in powdery mildew, as they always do. I've been looking for a chemical remedy but the only treatments on the shelf deal with ornamental plants only. Do you know of a product, or other remedy, that might help?
28 Jun, 2011
Answers
Washing the leaves well early in the morning usually stops powdery mildew, because when the spores are just sprouting, they can't stand liquid water--quite unlike all other fungi! If that still isn't sufficient, spray with wettable sulphur dust, or a mixture of organic washing up fluid and baking soda--1 tablespoon of washing up fluid and 2 teaspoons of baking soda to 1 gallon of water.
Note that sulphur dust is only safe when the temps are less than 29ยบ C.
29 Jun, 2011
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Are you watering enough, Matt? I think if you give the plants a fine spray every so often, it should get rid of the powdery mildew. This usually occurs in very dry ground. Annie
28 Jun, 2011