How to Manage Pests

UC Pest Management Guidelines

Cherry

Eutypa Dieback

Pathogen: Eutypa lata

(Reviewed 11/09, updated 11/09)

In this Guideline:

Symptoms and Signs

Eutypa dieback, also known as Cytosporina, gummosis, and limb dieback, causes limbs or twigs to wilt and die suddenly in late spring or summer with the leaves still attached. The bark has a dark discoloration with amber-colored gumming; infected areas in the interior of the wood are discolored brown.

Comments on the Disease

This fungus infects fresh pruning wounds when rainfall occurs 2 to 6 weeks after pruning. While infections can occur at any time of the year during rainy periods, the greatest incidence is in fall and winter.

Management

Remove infected limbs at least 1 foot below any sign of the disease. The preferred control method is to prune during July and August after harvest. There is less regrowth from pruning cuts if pruning is done in August. Ideally, pruning should be completed at least 6 weeks before the first fall rains. Wound treatments with paints or sealants have not been satisfactory because of lack of efficacy or difficulty in treating all of the pruning wounds immediately after being made. If pruning wounds are made outside of the preferred pruning period of July to August, use a fungicide to treat the wounds.

Common name		Amount per acre	R.E.I.‡	P.H.I.‡
(trade name)			(hours)	(days)
When choosing a pesticide, consider its usefulness in an IPM program by reviewing the pesticide's properties, efficacy, application timing, and information relating to resistance management, honey bees (PDF), and environmental impact. Not all registered pesticides are listed. Always read the label of the product being listed.
A.	THIOPHANATE-METHYL
	(Topsin M) WSB	1-1.5 lb/5 gal water	2 days	1
	MODE OF ACTION: A MBC (Group 1)1 thiophanate fungicide.
	COMMENTS: Recommended rate is 1.5 lb/A. Requires a Special Local Needs (Section 24C) registration.
‡	Restricted entry interval (R.E.I.) is the number of hours(unless otherwise noted) from treatment until the treated area can be safely entered without protective clothing. Preharvest interval (P.H.I.) is the number of days from treatment to harvest. In some cases the REI exceeds the PHI. The longer of two intervals is the minimum time that must elapse before harvest.
1	Group numbers are assigned by the Fungicide Resistance Action Committee (FRAC) according to different modes of actions (for more information, see http://www.frac.info/). Fungicides with a different group number are suitable to alternate in a resistance management program. In California, make no more than one application of fungicides with MODE-OF-ACTION GROUP numbers 1, 4, 9, 11, or 17 before rotating to a fungicide with a different MODE-OF-ACTION GROUP number; for fungicides with other Group numbers, make no more than two consecutive applications before rotating to fungicide with a different MODE-OF-ACTION GROUP number.

PUBLICATION

UC IPM Pest Management Guidelines: Cherry
UC ANR Publication 3440

Diseases

• J. E. Adaskaveg, Plant Pathology, UC Riverside
• J. L. Caprile, UC Cooperative Extension, Contra Costa County

Acknowledgment for contributions to Diseases:

• W. D. Gubler, Plant Pathology, UC Davis
• B. L. Teviotdale, Kearney Agricultural Center, Parlier

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