Powdery Mildew

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Powdery mildew is a very common fungal disease that attacks a broad range of plants.  It looks like a white or grey powdery coating on leaves of plants and spreads rapidly over foliage. On some plants it will also attack and distort young stems and flower buds. Infected tissue withers and dies.

It is important to control this disease quickly because of its rapid growth and to prevent its spread to other plants. If left untreated powdery mildew will kill most annuals and significantly weaken other plants.

Plants Attacked by Powdery Mildew
Many including grapes, roses, peas, geraniums, hydrangeas, gerberas, dahlias, rosemary, mint, zucchinis, annuals, crepe myrtles and more.

Rose leaves with early powdery mildew

Rose leaves with early powdery mildew

Organic Control Methods for Powdery Mildew

  • Spray with OCP eco-fungicide. It rapidly destroys the fungal growth (within 5 minutes) and leaves a protective coating against new spores germinating.
  • Adding OCP eco-seaweed into the spray mix will also help plants strengthen their foliage to fight off further attacks and reduce stress on the plant.
  • Leaves which are severely infected should be removed.

You may notice some yellow and black ladybeetles on plants with powdery mildew.  These ladybeetles feed on the mildew but unfortunately they are rarely able to control the disease alone.  eco-fungicide and eco-rose sprays are safe to use without harming them.

Zucchini leaf with powdery mildew (note the adult and juvenile ladybeetle feeding on the mildew)

Zucchini leaf with powdery mildew (note the adult and juvenile ladybeetle feeding on the mildew)

Cosmos foliage with powdery mildew

Cosmos foliage with powdery mildew

Pea leaves with powdery mildew

Pea leaves with powdery mildew