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How to Manage Pests
UC Pest Management Guidelines
Cherry
Powdery Mildew
Pathogen: Podosphaera clandestina
(Reviewed 4/06,
updated 4/06)
In this Guideline:
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Powdery mildew is marked by superficial, white, weblike growth on
leaves, shoots, or fruit.
The fungus overwinters in buds on twigs and as cleistothecia, which
are spore-containing structures, on the bark of twigs and branches. Secondary
spores produced in spring spread the fungus to new growth. Infections can be
severe in commercial orchards during years of low rainfall, high humidity, and
warm temperatures (70° to 80°F). The disease is particularly severe on new
growth, such as shoots of inner scaffolds, and can infect fruit as well,
causing direct crop loss. In warm, humid, coastal areas, powdery mildew can
also be severe after harvest.
To protect fruit, spray soon after petal fall and 2 to 3 weeks later
if needed. Treat immediately if mildew is found on leaves or shoots of inner
scaffolds. Do not use the same fungicide or fungicides with similar chemistry
more than twice in one year to reduce the potential for the development of
resistance by the pathogen to the fungicide. In orchards with a history of mildew, select fungicides
that are active against brown rot and gray mold, as well as powdery mildew
during bloom and immediately before harvest, being careful to note the
preharvest interval.
| Common name |
Amount/Acre |
P.H.I.+ |
| (trade name) |
|
(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.
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| A. |
FENARIMOL |
| |
(Rubigan) EC |
6–12 oz/200 gal water |
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MODE OF ACTION: A DMI (Group 3)1
pyrimidine fungicide.
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COMMENTS: Apply a treatment at late bloom to petal fall and
repeat at 14–21 day intervals as required for control until harvest. Do not apply more than 36 oz before harvest. |
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| B. |
MYCLOBUTANIL |
| |
(Rally) 40W |
2.5–6 oz |
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MODE OF ACTION: A DMI (Group 3)1
triazole fungicide.
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COMMENTS: Do not apply more than 3.2 lb product/acre/season.
More effective when applied as a concentrate (80-100 gal/acre) than as a dilute spray. |
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| C. |
TRIFLUMIZOLE |
| |
(Procure) 50W |
8-16 oz |
1 |
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MODE OF ACTION: A DMI (Group 3)1 triazole fungicide. |
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| D. |
QUINOXYFEN |
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(Quintec) |
7 fl oz |
7 |
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MODE OF ACTION: A quinoline (Group 13)1 fungicide. |
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COMMENTS: Apply 1-2 weeks after petal fall. If additional
treatments are necessary, rotate with a fungicide that has a different Group number. |
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| E. |
WETTABLE SULFUR# |
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(80-92% Sulfur) |
10–20 lb |
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MODE OF ACTION: A multi-site contact (Group M2)1
inorganic fungicide.
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COMMENTS: Do not enter treated areas for 24 hours unless
protective product clothing is worn. Do not apply within 3 weeks of an oil application. |
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| F. |
LIQUID LIME SULFUR# |
Label rates |
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MODE OF ACTION: A multi-site contact (Group M2)1
inorganic fungicide.
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COMMENTS: Do not enter treated areas for 48 hours unless
protective product clothing is worn. Do not apply within 3 weeks of an oil application. |
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| G. |
THIOPHANATE METHYL |
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(Topsin-M) 70WP |
0.5 lb/100 gal water
up to 1.5 lb/acre
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1 |
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MODE OF ACTION: A MBC (Group 1)1
thiophanate fungicide.
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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. |
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| H. |
PYRACLOSTROBIN/BOSCALID |
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(Pristine) |
10.5–14.5 oz |
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MODE OF ACTION: A Qol (Group 11)1 and carboxamide
(Group 7)1 fungicide.
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COMMENTS: To reduce the potential for the development of
resistance, do not make more than five applications/season of Group 7 or 11 fungicides. |
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| I. |
PROPICONAZOLE |
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(Bumper, Orbit) |
4 fl oz |
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MODE OF ACTION: A DMI (Group 3)1
triazole fungicide.
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COMMENTS: Apply at popcorn. Do not apply more than 8 fl oz/acre/crop. |
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| J. |
FENBUCONAZOLE |
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(Indar) 70WSP |
Label rates |
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MODE OF ACTION: A DMI (Group 3)1
triazole fungicide.
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| K. |
AZOXYSTROBIN |
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(Abound) |
11–15.4 fl oz |
0 |
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MODE OF ACTION: A Qol (Group 11)1 fungicide. |
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COMMENTS: Do not apply more than three sequential sprays of
this product before alternating with a fungicide with a different Group number. |
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More information on cherry fungicides
![[Precautions]](/IMAGES/btn-precautions_bul.gif)
![[UC Peer Reviewed]](/IMAGES/logo-ucpeerreviewed.jpg)
UC IPM Pest Management Guidelines: Cherry
UC ANR Publication 3440
Diseases
J. E. Adaskaveg, Plant Pathology, UC Riverside
W. D. Gubler, Plant Pathology, UC Davis
Acknowledgment for contributions to the diseases section:
B. L. Teviotdale, Kearney Agricultural Center, Parlier
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