Powdery Mildew in the Low Desert

HOST: Roses, Euonymous, cucurbits, grapes,vegetables, fruit trees, etc. - quite common on both cultivated and wild plants

SYMPTOMS:

White, powdery substance on leaves and stems

CAUSES:

Powdery Mildew is abundant in arid and semi arid areas, the spores do not require moisture. It is an obligate parasite. It lands on the leaf of a plant and redirects nutrients from the plant to itself. In severe cases it covers the leaves, blocking out the sun and inhibiting the plants ability to photosynthesize. It often occurs when sun loving plants are placed in the shade

MANAGEMENT:

• Select resistant plants

• Place plants in appropriate environment (adequate sun light & air circulation)

• After the new growth of affected plants reaches about six inches long and UNTIL THE TEMPERATURE REACHES 90 degrees F, you may apply dusting sulfur to foliage every 14 days.

• If necessary apply fungicide. Fungicide works much better as a preventative measure, before the powdery mildew becomes a problem.