How to Manage Pests

UC Pest Management Guidelines

SYMPTOMS

Leaves produced in spring are thickened, curled, and colored red or yellow instead of normal green. Severely affected shoots die. Irregular, reddish lesions are sometimes seen on fruit. Badly diseased leaves fall by early summer, and repeated infections debilitate trees and kill branches.

COMMENTS ON THE DISEASE

Taphrina deformans survives on tree surfaces and buds and is favored by wet weather during spring.

MANAGEMENT

Peach leaf curl can be a serious problem, especially on many of the low-chilling varieties and when spring weather is unusually wet. This disease is usually kept under control with a dormant fungicide application.

Organically Acceptable Methods
Spraying with Bordeaux mixture or copper is acceptable in an organically certified crop.

Chemical Control
One application in the dormant/delayed dormant period is sufficient except in areas of high rainfall or where leaf curl has become an increasing problem. In such cases, an added application either in the fall or at the delayed dormant timing in late winter before bud swell is recommended. If heavy rains are occurring as leaves emerge in spring, consider an application of ziram.

Common name		Amount to Use	R.E.I.+	P.H.I.+
(trade name)			(hours)	(days)
The following materials are listed in order of usefulness in an IPM program, taking into account efficacy. When choosing a pesticide, also consider information relating to environmental impact. Not all registered pesticides are listed. Always read label of product being used.
A.	ZIRAM 76DF	8–10 lb/acre	48	30
	MODE OF ACTION GROUP NAME (NUMBER1): Multi-site contact (M3)
	COMMENTS: While not a preferred timing, if heavy rains are occurring as leaves are emerging in spring or disease symptoms are present, an application of ziram can be beneficial in helping to reduce the spread of the fungus.
B.	FIXED COPPER#
	(various products)	Label rates	see label	see label
	MODE OF ACTION GROUP NAME (NUMBER1): Multi-site contact (M1)
	COMMENTS: Not all copper compounds are approved for use in organic production; check product.
C.	CHLOROTHALONIL
	(Echo 720)	3.125–4.125 pt/acre	12	NA
	(Bravo Ultrex DF)	2.8-3.8 lb/acre	12	0
	(Bravo Weather Stik)	3.125–4.125 pt/acre	12	0
	MODE OF ACTION GROUP NAME (NUMBER1): Multi-site contact (M5)
	COMMENTS: Do not use with or closely following oil sprays.
D.	BORDEAUX MIXTURE#
	10:10:100	Label rates	see label	see label
	MODE OF ACTION GROUP NAME (NUMBER1): Multi-site contact (M1)
	COMMENTS: For information on making Bordeaux mixture, see UC IPM Pest Note: Bordeaux Mixture, ANR Publication 7481. Check copper label to determine if organically acceptable.
+	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.
#	Acceptable for use on organically grown produce.
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 a fungicide with a different mode of action Group number.
NA	Not applicable.

PUBLICATION

UC IPM Pest Management Guidelines: Nectarine
UC ANR Publication 3451
Diseases
J. E. Adaskaveg, Plant Pathology, UC Riverside
R. A. Duncan, UC Cooperative Extension Stanislaus County
K. R. Day, UC Cooperative Extension, Tulare County
Acknowledgment for contributions to Diseases:
B. L. Teviotdale, Kearney Agricultural Center, Parlier
W. D. Gubler, Plant Pathology, UC Davis

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