It’s such a shame to see your healthy squash plants rapidly fall to powdery mildew. After all of the work you have done, raising them from seed.
But there are methods you can call upon to prevent this.
The causes of powdery mildew
Now that summer is well underway, or as I like to call it, “the rain season”, the increase in humidity will accelerate the likelihood that your prize courgettes, pumpkins and cucumbers will succumb to powdery mildew. This common condition manifests itself as powdery white blotches on leaves and eventually leads to leaves turning yellow and dying.
Bring out the baking soda!
Rather than nipping out to the local garden centre for a nasty chemical solution, all you need to do is spray your plants with a mixture of baking soda and water onto both sides of infect leaves. I use 1 tablespoon of baking soda to 1 gallon (4.5 litres) of water. It is highly important that you spray both sides of the leaves; the fungus actually forms on the underside and fruits on the topside of the leaf. Using baking soda actually lowers the acidity and raises the PH of the plant which in turn compromises the environment that this fungus thrives in.
Badly infected leaves may be removed and burned. Do not put them onto the compost heap as this will only compound your problems and allow the fungus to spread across your garden. Don’t rely on this method as breaking any part of the plant may lead to other types of infection. Your best bet is to treat your plants as early as possible.
This same treatment can be used on other vegetables and flowering plants. Continue treatment for 3 or 4 days to ensure that you have eradicated the fungus.
Anti-mildew recipe again
1 tablespoon of baking soda
1 gallon (4.5 litres) of water
Spray the top and undersides of every leaf. Do this daily.