• Rose leaves with powdery mildew

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Powdery Mildew

Powdery mildew is a common disease infecting a wide range of plants, covering leaves with a dense, greyish powder.


Powdery mildew diseases are very common. Many vegetables, bedding plants, fruit crops, shrubs and trees can be infected. Typically infected leaves and shoots are discoloured, distorted and covered in a dense, greyish coloured powder like material.

Powdery mildew is most common in Summer and Autumn when the weather is warm and humid.

Downy mildew has similar symptoms except the greyish powdery material is on the undersides of leaves.


Prune out infected shoots of plants and destroy, by burning if possible. Keep plants well spaced and improve ventilation around them.

Fruit trees, grapes and vegetables > Apply Organic Super Sulphur as advised on the label instructions.

Roses and ornamentals > Apply PLANThealth Rose Force regularly every 14 days to treat infected plants. Once disease is controlled you can use Spectrum as a preventative treatment.

Disease is often carried between plants by sap sucking insects. Use Organic Super Spraying Oil to control these insects before they can spread disease.

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