Symptoms and Signs
Blackberry and raspberry plants with Cladosporium fruit rot have berries that are covered with a velvety, olive-green mycelial growth. While this growth is unsightly, it does not often damage the fruit. C. cladosporoides can occur alone or in association with lesions caused by Botrytis cinerea (the causal agent of Botrytis fruit rot).
Comments on the Disease
Cladosporium fruit rot of caneberry is primarily a postharvest storage disease. Even though these fungi cause little actual damage to fruit, the mycelial growth on the fruit is unappealing, so the fruit is unmarketable. Optimal temperature for the growth of these fungi is between 68° to 77°F (20° to 25°C), but may occur at lower temperatures during normal fruit storage.
This fruit rot is most commonly associated with fruit that is sunburned or damaged in some manner.
Management
Practice good sanitation and manage moisture within the planting to reduce inoculum levels and the risk of infestation. Harvest regularly and carefully, removing damaged and infected fruit. Cool berries as rapidly as possible to an optimum of 32°F (0°C).
Organically Acceptable Methods
Good sanitation and harvest practices are acceptable methods in an organically certified crop.
Treatment Decisions
Treat if weather conditions are favorable for the development of Botrytis and Cladosporium fungi (i.e., rain).
| Common name | Amount per acre | REI‡ | PHI‡ | |
|---|---|---|---|---|
| (Example trade name) | (hours) | (days) | ||
| Not all registered pesticides are listed. The following are ranked with the pesticides having the greatest IPM value listed first—the most effective and least likely to cause resistance are at the top of the table. When choosing a pesticide, consider information relating to the pesticide's properties and application timing, honey bees, and environmental impact. Always read the label of the product being used. | ||||
| A. | CYPRODINIL+FLUDIOXONIL | |||
| (Switch 62.5 WG) | 11–14 oz | 12 | 0 | |
| MODE-OF-ACTION GROUP NAME (NUMBER1): Anilinopyrimidine (9) and Phenylpyrrole (12) | ||||
| COMMENTS: Do not apply more than 56 oz/acre per year. | ||||
| B. | IPRODIONE | |||
| (Rovral 4F) | 1–2 pt | 24 | 0 | |
| MODE OF ACTION GROUP NAME (NUMBER1): Dicarboximide (2) | ||||
| COMMENTS: Apply in a minimum of 100 gal water/acre. Do not make more than 4 applications per crop per season. | ||||
| ‡ | Restricted entry interval (REI) is the number of hours (unless otherwise noted) from treatment until the treated area can be safely entered without protective clothing. Preharvest interval (PHI) 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. 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. |