Powdery Mildew

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Powdery mildew is a fungal disease that causes a layer of white powdery spores to cover the leaves of plants in the Cucurbitaceae, Solanaceae, and Fabaceae vegetable plant families. 

It is possible for mature plants to be only mildly affected by powdery mildew. Still, if left unchecked, it can spread rapidly, slowing plant growth, stalling fruit production, and eventually killing plants.

Extensive powdery mildew on peas

Managing powdery mildew

Ensure good air circulation. Space plants far enough apart to allow for air to circulate between them. If plants become overgrown, prune them carefully. Never cut away more than one-third of a plant at one time.

Grow resistant varieties. If powdery mildew is chronic in your garden, try looking for new hybrid varieties that are resistant.

Maximize sun. To the best of your abilities, make sure your plants don’t get more shade than they need for healthy growth. Powdery mildew does not spread as fast or as far in the sun. 

Prevent the spread. Watering your plants from above can increase the spread of powdery mildew as the spores are carried over other plants by water dripping down. Instead, try watering directly at ground level so there is less chance for dripping water to spread disease over other leaves or plants. 

Prune away infected leaves early. Sterilize tools and be careful when transporting infected leaves through your garden. The spores can survive in compost so dispose of infected leaves and plants by throwing them away or burning them.

Baking soda can also be an effective control measure with little negative environmental impact. To use, combine 1 tsp of baking soda with 1 litre of water in a spray bottle and mist the infected leaves daily.

Progression of powdery mildew on peas

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