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Melon · Cucumis melo

Why are there white spots on my melon leaves?

Those dusty white spots are almost certainly powdery mildew, a common fungal issue for melons. Check your plant's airflow and moisture levels first to see if conditions are too stagnant.

spots on a plant
Photo: Scot Nelson, CC0

Check these first

  1. Inspect the undersides of leaves for tiny insects.
  2. Check if the air around the plant is stagnant.
  3. Look for white dust on the upper leaf surfaces.

Likely causes

  1. Powdery Mildew

    Most likely

    How to tell: White, powdery patches appear on the top of leaves, eventually causing them to turn yellow and dry out. It spreads quickly in humid, still air.

    What to do: Remove the most heavily infected leaves immediately to stop the spread. Spray the remaining foliage with a mixture of one tablespoon of baking soda per gallon of water, applying it every 7 to 10 days.

  2. Bacterial Wilt

    Possible

    How to tell: Leaves develop spots followed by sudden wilting and death of entire vines. This is often spread by cucumber beetles.

    What to do: Remove and destroy the entire plant if you see signs of wilt, as it cannot be cured. Focus on controlling cucumber beetle populations early in the season to prevent future outbreaks.

When to worry

If the spots cover more than half the foliage or the vine begins to wilt, the plant is likely compromised. A few small spots are manageable with prompt treatment.

Stopping it coming back

Space your plants well to ensure good airflow and always water at the base of the plant rather than overhead to keep leaves dry.

Not sure which one it is? Photograph your melon.

This page lists the usual causes. Pocket Botanist looks at your actual leaf and tells you the likely cause, how serious it is, and what to try first. Identification and a health check are free.

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Questions people ask

Will the fruit be safe to eat if the leaves have spots?
Yes, the fruit is safe to eat as long as it is not damaged. Focus on keeping the plant healthy enough to finish ripening the melon.
Can I use a fungicide?
Yes, you can use a sulfur-based fungicide or a neem oil spray. Apply it in the early morning or evening to avoid burning the leaves in the sun.

More problems with Melon

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This article was generated with AI from the plant’s care profile and is general information, not horticultural advice. Read about how we build these guides.