Powdery Mildew Plant Disease

Pumpkin Plant Disease

About Powdery Mildew

Powdery Mildew is a common plant disease. It occurs all around the world. Many plants are highly susceptible to this plant disease. And the plant can succumb quickly to an infestation. Other plants are completely immune to it. It can affect flowers, vegetables, herbs, fruits, and even weeds!

Powdery Mildew is an airborne disease. It spreads quickly from plant to plant by insects. Insect control helps to control this disease.

Powdery mildew thrives in hot, humid, and wet weather. It spreads extremely fast. Many gardeners report no sign of it one day, and a major infestation the next.

The disease can be stopped and killed. Effective treatment requires early identification and treatment. Better still, apply fungicides before it arrives.

Fungicides usually work well. However, it will not cure the affected leaves of the ugly white spots.

Identifying Powdery Mildew

This disease is easy to spot.  A white, powdery (some call it cottony or sugary),  substance begins to appear on the leaves of your plants. It spreads very quickly. Left untreated, the disease quickly covers the entire leave, killing leaves and plants.

In the picture above, the pumpkin leaves on the left are healthy. The ones on the right side of the picture have powdery mildew disease. You can see that one of the leaves is entirely covered with mildew.

Avoiding Powdery Mildew

The best method of controlling powdery mildew is to avoid it. And, that means eliminating the environment it needs to thrive. It thrives in warm, humid, rainy weather. It likes dark and cloudy conditions. Dense foliage results in poor air circulation, creating the perfect place for powdery mildew to get a toehold in your plants. Moisture on the leaves also helps the rapid growth of the disease.

You can’t change the weather. But, there are a few things you can do.

  • Water plants during the daytime. Allow plenty of time for the leaves to dry before nightfall.
  • Water plants from the bottom, keeping the leaves dry.  
  • Thin bushy plants to increase air circulation through the foliage, and provide additional light to the remaining leaves.

How to Treat Powdery Mildew

Apply fungicides as soon as the problem is identified. Better yet, apply a fungicide just the start of hot, humid weather. Affected areas of leaves will not be cleaned of the white mildew. But, it stops the spread of the disease and kills the existing mildew. Regular treatment with fungicide is recommended.

Powdery Mildew grows on both the top and undersides of leaves, as well as the stem or vine. Apply fungicide to all parts of the plant.

If the affected area is minimal, remove unsightly, affected leaves.

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