How to Manage Pests

UC Pest Management Guidelines

Cladosporium leaf spot is characterized by round, tan leaf spots that rarely exceed 0.25 inch in diameter. Dark green spores and mycelium later develop in the centers of these spots. The presence of dark green sporulation distinguishes Cladosporium leaf spot from anthracnose and Stemphylium leaf spot diseases, both of which also form circular lesions.

Cladosporium leaf spot occurs to some extent almost every year. However, the disease is rarely severe unless there are significant rains in spring. This pathogen is seedborne.

Treatment is rarely necessary. If used, copper sprays must be applied as protectants.

Common Name		Amount/Acre
(trade name)
A.	COPPER HYDROXIDE	Label rates
	MODE OF ACTION: A multi-site contact (Group M)1 inorganic fungicide.
	COMMENTS: Copper sprays are not very effective. Apply as a protectant spray at 10–14 day intervals. Rate often depends upon disease severity. A suitable agricultural spray oil is recommended for use with some copper formulations. Consult label for specific application guidelines.

1	Group designations are assigned by the Fungicide Resistance Action Committee (FRAC) according to different modes of actions. Fungicides with a different group designation are suitable to alternate in a resistance management program. For more information, see www.frac.info/.

PUBLICATION

UC IPM Pest Management Guidelines: Spinach
UC ANR Publication 3467
Diseases
S. T. Koike, UC Cooperative Extension, Monterey Co.
M. LeStrange, UC Cooperative Extension, Tulare Co.
F. F. Laemmlen, UC Cooperative Extension, Santa Barbara Co.

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