How to Manage Pests

UC Pest Management Guidelines

SYMPTOMS

Fruit rot caused by Monilinia or Botrytis species results in dark brown, firm, circular spots that spread rapidly over fruit. Tan spore masses may grow on the rotted areas. The fruit become more susceptible as they ripen. Diseased fruits usually do not remain on the tree until the next season, but are present as inoculum sources for the current season's crop.

Rhizopus rot is a postharvest storage problem. The decaying fruit tissue is watery and soft; the fungus is identified by masses of white mycelium with tiny black sporangia that form most abundantly on fruit near the edge of containers.

COMMENTS ON THE DISEASES

Monilinia and Botrytis species can infect uninjured ripening fruit. Moisture, either rain or dew, and injury or fruit cracking increases the probability of preharvest infection and consequent rot. Rhizopus invades ripe fruit that has been injured or cracked, causing the fruit to rot after harvest.

MANAGEMENT

Injured, split fruits cannot be protected from rots caused by Monilinia and Botrytis by preharvest sprays, but uninjured fruit can. The best fungicide to use for control depends on whether Botrytis is present alone, Monilinia alone, or both are present. Since it is not practical to try to distinguish the species present, the best treatment materials tend to be those that effectively control both species.

Protect ripe fruit from Rhizopus either with a preharvest treatment (for fruit that will be sold right after harvest) or a postharvest treatment (for fruit that will be shipped). After harvest, Rhizopus can be controlled if the fruit is stored below temperatures of 40°F. Apply a preharvest treatment 1 to 14 days before harvest. A postharvest spray can be made during stem cutting and sizing operations.

Common name		Amount/Acre	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.
PREHARVEST: Monilinia and Botrytis (fungicides below are effective against both species)
A.	FENHEXAMID
	(Elevate) 50WDG	1–1.5 lb	12	0
	MODE OF ACTION GROUP NAME (NUMBER1): Hydroxyanilide (17)
	COMMENTS: Do not apply more than 6 lb/acre/season or make more than 2 consecutive applications with this product.
B.	TEBUCONAZOLE/TRIFLOXYSTROBIN
	(Adament) 50WP	8 oz	24	1
	MODE OF ACTION GROUP NAME (NUMBER1): Demethylation inhibitor (3) and Quinone outside inhibitor (11)
C.	TEBUCONAZOLE
	(Elite) 45WP	4–8 oz	12	0
	MODE OF ACTION GROUP NAME (NUMBER1): Demethylation inhibitor (3)
D.	PYRACLOSTROBIN/BOSCALID
	(Pristine)	10.5–14.5 oz	12	0
	MODE OF ACTION GROUP NAME (NUMBER1): Quinone outside inhibitor (11) and Carboxamide (7)
	COMMENTS: To reduce the potential for the development of resistance, do not make more than two applications/season of Group 7 or 11 fungicides.
E.	THIOPHANATE METHYL
	(Topsin-M) 70WP	0.5 lb/100 gal water up to 1.5 lb/acre	12	1
	MODE OF ACTION GROUP NAME (NUMBER1): Methyl benzimidazole (1)
	COMMENTS: Use only once a year. Do not use in orchards where resistance has been observed. Use only in combination or in an alternating application program with a fungicide with a different Group number. Resistant populations to benzimidazole fungicides may result in low performance or a failed fungicide treatment.
F.	CAPTAN
	(Various) 50WP	Label rates	4 days	0
	MODE OF ACTION GROUP NAME (NUMBER1): Multi-site contact (M4)
	COMMENTS: Do not apply in combination with, immediately before, or closely following oil sprays.
POSTHARVEST: Rhizopus only
A.	DICHLORAN
	(Botran) 75W	1.33 lb/acre	12	10
	MODE OF ACTION GROUP NAME (NUMBER1): Aromatic hydrocarbon (14)
	COMMENTS: Apply 10 days before harvest.
POSTHARVEST: Monilinia, Botrytis, and Rhizopus
A.	TEBUCONAZOLE
	(Elite) 45WP	8 oz/25,000 lb fruit	NA	NA
	MODE OF ACTION GROUP NAME (NUMBER1): Demethylation inhibitor (3)
	COMMENTS: For use on sweet cherries. Special Local Needs registration. Labeled for one postharvest application.
B.	FENHEXAMID
	(Judge) 50WDG	1.5 lb/25,000 lb fruit	12	NA
	MODE OF ACTION GROUP NAME (NUMBER1): Hydroxyanilide (17)
	COMMENTS: Do not apply more than 6 lb/acre/season including preharvest applications. For post-harvest application to fruit, apply only once.
C.	FLUDIOXONIL
	(Scholar)	8–16 oz/25–100 gal	NA	NA
	MODE OF ACTION GROUP NAME (NUMBER1): Phenylpyrrole (12)
	COMMENTS: Treat 25,000 lb fruit in a high volume (dilute) application with agitation to keep Scholar in solution. Labeled for one postharvest application.
+	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.
NA	Not applicable.

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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