How to Manage Pests

UC Pest Management Guidelines

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Pistachio

Powdery Mildew

Pathogens: Oidium sp.

(Reviewed 2/07, updated 2/09)

In this Guideline:

Symptoms
Comments on the disease
Management

SYMPTOMS

Powdery mildew starts as white powdery blotches on leaves, leaf stems, and fruit epicarp. Later in the season, these blotches turn brown to black and have a netted appearance. The blotches on fruit become russeted and cause the fruit to become misshapened. Multiple blotches like this cause leaves to yellow, then brown and die. Infected tissues may be distorted and misshapen. Similar symptoms can be found on rachises, fruit stems, petioles, underside of leaf blades, and young shoots.

COMMENTS ON THE DISEASE

The disease commonly occurs on the Trabonella cultivar. Red Aleppo is more susceptible than the Kerman cultivar.

MANAGEMENT

The occurrence of powdery mildew on pistachio trees is uncommon and sporadic. No control measures are recommended.

PUBLICATION

UC IPM Pest Management Guidelines: Pistachio
UC ANR Publication 3461
Diseases
T. J. Michailides, Kearney Agricultural Center, Parlier
Acknowledgment for contributions to Diseases:
B. L. Teviotdale, Kearney Agricultural Center, Parlier

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