Advice for novice gardner with a white powdery mildew problem - Ask Extension
Hello,
My cucumber plant and my pumpkin plant both have white powder mildew, with the telltale white spots. There are a lot of suggestions online for...
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Advice for novice gardner with a white powdery mildew problem #879510
Asked July 30, 2024, 10:12 PM EDT
Hello,
My cucumber plant and my pumpkin plant both have white powder mildew, with the telltale white spots. There are a lot of suggestions online for getting rid of it. What is the best way to tackle it before the leaves begin to turn yellow and the plant starts to slowly die, as I watched happen to my cucumber plants last year?
Thank you in advance for any advice that you provide.
Summit County Ohio
Expert Response
Good Morning Sherry!
Thank you for letting me help you with your cuke/pumpkin problem.
As you know powdery mildew is a somewhat common problem within the cucurbit family. It usually starts in July, and loves hot, humid weather. The disease spreads its spores on the wind.
The first line of protection is to purchase seeds or starts that are varieties resistant to powdery mildew. This should be stated on the seed package or the tag in the plant starters.
2nd, don’t plant your new plants in the same area that you had them in the previous year.
Make sure that your plants do not get any shade.
To help combat the disease currently on your plants you will have to use some fungicides. Make sure that the ones you use are made for edibles! You will want to rotate your fungicides as some variants are more susceptible to one fungicide than another. Here are some suggestions:
If there are not too many infected leaves, remove them. If plant is totally infected, get the worst ones off before spraying.
Remember also to use good sanitation methods cleaning up all leaves that fall to the ground.
Here is a fact sheet if you care to read it. This explains a lot about the disease, but the chemicals are for commercial growers.
https://u.osu.edu/miller.769/2023/07/29/powdery-mildew-management-in-cucurbits/
hope this helps!!
Thank you for letting me help you with your cuke/pumpkin problem.
As you know powdery mildew is a somewhat common problem within the cucurbit family. It usually starts in July, and loves hot, humid weather. The disease spreads its spores on the wind.
The first line of protection is to purchase seeds or starts that are varieties resistant to powdery mildew. This should be stated on the seed package or the tag in the plant starters.
2nd, don’t plant your new plants in the same area that you had them in the previous year.
Make sure that your plants do not get any shade.
To help combat the disease currently on your plants you will have to use some fungicides. Make sure that the ones you use are made for edibles! You will want to rotate your fungicides as some variants are more susceptible to one fungicide than another. Here are some suggestions:
- Monterey Bi-Carb Old Fashioned Fungicide
- Bonide Fung-onil
- Liqui-Cop – copper products are best used in rotation with other fungicides (copper can be in the rotation, but is not as effective as the others)
If there are not too many infected leaves, remove them. If plant is totally infected, get the worst ones off before spraying.
Remember also to use good sanitation methods cleaning up all leaves that fall to the ground.
Here is a fact sheet if you care to read it. This explains a lot about the disease, but the chemicals are for commercial growers.
https://u.osu.edu/miller.769/2023/07/29/powdery-mildew-management-in-cucurbits/
hope this helps!!
Thank you! I really appreciate all of the information.
I'm finding that the Monterey Bi-Carb Old Fashioned Fungicide is sold out everywhere (possibly discontinued?). Do you know of an another product that's similar?
Kind regards,
Sherry
Hi Sherry,
These are similar. Rotation is the key. Think overuse of antibiotics. All of these were found on amazon, but garden centers or places like Home Depot or Lowes may also carry them.
Good Luck and let me know if you have any other questions.
These are similar. Rotation is the key. Think overuse of antibiotics. All of these were found on amazon, but garden centers or places like Home Depot or Lowes may also carry them.
Good Luck and let me know if you have any other questions.
Monterey Liquid Copper
Fungicide RTU - Organic Gardening Fungicide for Flowers, Fruits, & Vegetables - 32 oz
Fungi-Max
Bonide Fung-onil Multi-Purpose, 32 oz Concentrated
Solution for Plant Disease Control, Long Lasting & Waterproof concentrate
