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How to Manage Pests
UC Pest Management Guidelines
Almond
Green Fruit Rot (Jacket Rot)
Pathogens: Botrytis cinerea, Sclerotinia sclerotiorum, Monilinia
laxa
(Reviewed 1/05,
updated 1/05)
In this Guideline:
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Green fruit rot begins during the latter part of the bloom period when the
fungus infects senescing petals and
anthers. Infected petals develop water-soaked brown spots. Some infected
petals may fall onto leaves causing secondary infections. Anther infections can
spread to floral tubes or flower jackets causing them to wither and stick to
developing fruit. As fruit sets and starts to grow, a brown spot develops where
the jacket sticks to it. Frequently this leads to rot of the entire fruit.
This disease is of little importance in many years, but when conditions are
cool and conditions wet during bloom, it can cause severe losses. One or more
of several pathogens may be involved.
When bloom is extended and moisture is abundant, apply a fungicide at full
bloom to prevent green fruit rot. Continue treatment until rain stops. Be sure
the fungicide you choose is effective against all three potential pathogens;
demethyation (sterol) inhibitor fungicides such as myclobutanil (Laredo) and
propiconazole (Break/Orbit) are not effective against Botrytis cinerea.
| Common name |
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P.H.I.+ |
|---|
| (trade name) |
Amount/Acre |
(days) |
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| Fungicides are listed in general order of efficacy. |
| A. |
CYPRODINIL |
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(Vangard) WG |
5 oz |
150 days |
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COMMENTS: Chemical class: anilinopyrimidine. Do not
apply more than 30 oz/acre/crop/year. |
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| B. |
BOSCALID/PYRACLOSTROBIN |
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(Pristine) |
10.5-14.5 oz |
see comments |
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COMMENTS: Chemical class: carboxyanilide/strobilurin.
See label for current preharvest interval. Do not make more than 4 applications
per season of strobilurins or carboxyanilides to limit the potential for the
development of resistance. |
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| C. |
IPRODIONE |
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(Rovral) 4F |
1 pt |
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(Rovral) 50WP |
1 lb |
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COMMENTS: Chemical class: dicarboximide. Addition of
a narrow range oil (superior, supreme) at 1 to 2% volume/volume increases the
effectiveness of this material. Do not apply oil, however, within 3 weeks of a
sulfur application or closely before or after an application of captan or
chlorothalonil. Do not apply more than 4 applications/season. |
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| D. |
THIOPHANATE-METHYL |
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(Topsin-M) 70WP |
1.5-2 lb |
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COMMENTS: Chemical class: benzimidazole. Strains of
brown rot pathogen resistant to thiophanate-methyl have been found on almond,
but resistance is not widespread. Do not apply more than 3 lb/season/acre. |
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| E. |
CAPTAN |
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(various) 50WP |
8 lb |
30 |
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COMMENTS: Chemical class: phthalamide. Do not apply
in combination with, immediately before, or closely following oil sprays. |
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More information on almond fungicides
![[Precautions]](/IMAGES/btn-precautions_bul.gif)
![[UC Peer Reviewed]](/IMAGES/logo-ucpeerreviewed.jpg)
UC IPM Pest Management Guidelines: Almond
UC ANR Publication 3431
Diseases
W. D. Gubler, Plant Pathology, UC Davis
J. E. Adaskaveg, Plant Pathology, UC Riverside
Roger Duncan, UC Cooperative Extension, Stanislaus County
J. J.
Stapleton, UC IPM Program, Kearney Agricultural Center
Acknowledgment for contributions to the disease section:
B. L. Teviotdale, Kearney Agricultural Center, Parlier
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