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How to Manage Pests
UC Pest Management Guidelines
Caneberries
Late Leaf Rust
Pathogen: Pucciniastrum americanum
(Reviewed 5/08,
updated 5/08)
In this Guideline:
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Late leaf rust infects red and purple raspberry and is not a
systemic pathogen. As the name late leaf rust suggests, later in the season
(beginning in July) many small rust spots are found on the older, lower leaves
of raspberries. These spots first turn yellow and then brown. In severe cases
plants can be defoliated, and the rust can also infect flowers and fruit.
Yellow uredinia and powdery urediniospores form on the bottom sides of leaves.
In fall, telia and teliospores appear as brown growth within existing uredinia.
Because this pathogen's alternate host, white spruce (Picea
glauca), is not
common in coastal California where caneberries are cultivated, the fungus
probably overwinters as mycelium within remaining canes and produces urediniospores
in spring. These spring urediniospores then infect growing plants. Spores of P.
americanum are spread by
wind, and infection of leaves is favored by high relative humidity.
As with yellow rust, any method that improves air circulation in the
raspberry hedgerow is helpul in mitigating the spread and development of this
disease. Also, the removal of infected floricanes and primocanes is useful in
that it removes an important source of inoculum.
| Common name |
Amount/Acre |
R.E.I.+ |
P.H.I.+ |
| (trade name) |
|
(hours) |
(days) |
|
| When
choosing a pesticide, consider the general
properties of the fungicide as well as information relating to
environmental impact.
|
| |
| DELAYED
DORMANT
|
| A. |
FIXED COPPERS# |
Label rates |
24 |
0 |
| |
MODE
OF ACTION GROUP NAME (NUMBER1): Multi-site contact (M1)
|
| |
COMMENTS:
For organically certified produce, check with your certifier for acceptable copper formulations. |
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| FIRST
BLOOM
|
| A. |
FIXED COPPERS# |
Label rates |
24 |
0 |
| |
MODE
OF ACTION GROUP NAME (NUMBER1): Multi-site contact (M1)
|
| |
COMMENTS:
For organically certified produce, check with your certifier for acceptable copper formulations. |
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| B. |
PYRACLOSTROBIN/BOSCALID |
| |
(Pristine) |
18.5–23 oz |
12 |
0 |
| |
MODE
OF ACTION GROUP NAME (NUMBER1): Quinone outside inhibitor (11) and Carboxamide (7) |
| |
COMMENTS:
Restricted entry interval is 12 hours.
To limit the potential for development of resistance, do not apply
more than 4 application of this or other Group 7 and 11 fungicides per season. |
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| C. |
PYRACLOSTROBIN |
| |
(Cabrio) EG |
14 oz |
24 |
0 |
| |
MODE
OF ACTION GROUP NAME (NUMBER1): Quinone outside inhibitor (11)
|
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COMMENTS:
Restricted entry interval: 24 hours.
Do not make more than two sequential applications before alternating to a product with a different mode of action Group number. |
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| D. |
MYCLOBUTANIL |
| |
(Rally) 40WSP |
1.25–1.5 oz |
24 |
0 |
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MODE
OF ACTION GROUP NAME (NUMBER1): Demethylation inhibitor (3)
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COMMENTS:
Initiate applications as early as budbreak and continue at 10- to 14-day
intervals. Shorter intervals may be used under heavy disease pressure. Do not apply more than 10 oz/acre/season. |
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| E. |
TRIADIMEFON |
| |
(Bayleton) 50DF |
4 oz |
12 |
1 |
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MODE
OF ACTION GROUP NAME (NUMBER1): Demethylation inhibitor (3)
|
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COMMENTS:
For use on raspberries only. Restricted entry interval is 12 hours. Apply in
not less than 20 gal water/acre using ground equipment. Make additional
applications at 4- to 6-week intervals as needed, not to exceed 7 applications in one year or 2 applications within the same 30-day period. |
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![[Precautions]](/IMAGES/btn-precautions_bul.gif)
![[UC Peer Reviewed]](/IMAGES/logo-ucpeerreviewed.jpg)
UC IPM Pest Management Guidelines: Caneberries
UC ANR Publication 3437
Diseases
S. T. Koike, UC Cooperative Extension, Monterey County
M. P. Bolda, UC Cooperative Extension, Santa Cruz County
E. J. Perry, UC Cooperative Extension, Stanislaus County
W. D. Gubler, Plant Pathology, UC Davis
L. J. Bettiga, UC Cooperative Extension, Monterey County
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