Agriculture: Cherry Pest Management Guidelines

Brown Rot Blossom and Twig Blight

  • Brown rot blossom and twig blight: Monilinia fructicola, Monilinia laxa
  • Symptoms and Signs

    Brown rot infection occurs through blossom parts and progresses into the twig, killing blossoms, spurs, and associated leaves. Small cankers on twigs form below infected spurs; gum may be present at the base of flowers and dead flowers remain on the tree. Beige-colored spore masses develop on diseased flowers under high humidity.

    Comments on the Disease

    Infection is favored by rain or dew during bloom and moderate temperatures (about 58°to 77°F).

    Management

    Cherries are the least susceptible stone fruit to this disease and preventive sprays may not be needed unless the weather is favorable for infection or the orchard has a history of this disease. One and sometimes two applications may be necessary and are most effective when made sufficiently in advance of rain so that the spray has time to dry. Start treatment at the popcorn stage of bloom. To provide adequate continuing protection, spray every 14 days until bloom is completed. When continued heavy rainfall is occurring or other conditions are conducive to infection, shorten this interval to 10 days. Aerial applications are generally not as effective as properly applied ground sprays but may be necessary when the orchard floor is too wet.

    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. AZOXYSTROBIN/DIFENCONAZOLE
    (Quadris Top) 12–14 fl oz 12 0
    MODE-OF-ACTION GROUP NAME (NUMBER1): Quinone outside inhibitor (11) and Demethylation inhibitor (3)
    COMMENTS: Resistance to FRAC 3 and FRAC 11 group fungicides is possible in fungal populations. Use only when alternating with a fungicide that has at least one different FRAC Group number.
    B. AZOXYSTROBIN/PROPICONAZOLE
    (QuiltXcel) 14 fl oz 12 0
    MODE-OF-ACTION GROUP NAME (NUMBER1): Quinone outside inhibitor (11) and Demethylation inhibitor (3)
    COMMENTS: Resistance to FRAC 3 and FRAC 11 group fungicides is possible in fungal populations. Use only when alternating with a fungicide that has at least one different FRAC Group number.
    C. TEBUCONAZOLE/TRIFLOXYSTROBIN
    (Adament 50WG) 4–8 fl oz 120 (5 days) 1
    MODE-OF-ACTION GROUP NAME (NUMBER1): Quinone outside inhibitor (11) and Demethylation inhibitor (3)
    COMMENTS: Resistance to FRAC 3 and FRAC 11 group fungicides is possible in fungal populations. Use only when alternating with a fungicide that has at least one different FRAC Group number.
    D. FLUOPYRAM/TRIFLOXYSTROBIN
    (Luna Sensation) 5.0–5.6 fl oz 12 1
    MODE-OF-ACTION GROUP NAME (NUMBER1): Succinate dehydrogenase inhibitor (7) and Quinone outside inhibitor (11)
    COMMENTS: Resistance to FRAC 7 and FRAC 11 group fungicides is possible in fungal populations. Use only when alternating with a fungicide that has at least one different FRAC Group number.
    E. PENTHIOPYRAD
    (Fontelis) 14–20 fl oz 12 0
    MODE-OF-ACTION GROUP NAME (NUMBER1): Succinate dehydrogenase inhibitor (7)
    COMMENTS: Resistance to FRAC 7 group fungicides is possible in fungal populations. Use only when alternating with a fungicide that has a different FRAC Group number.
    F. TEBUCONAZOLE
    (Elite 45WP) 4–8 oz 120 (5 days) 0
    MODE-OF-ACTION GROUP NAME (NUMBER1): Demethylation inhibitor (3)
    G. PROPICONAZOLE
    (Bumper) 4 fl oz 12 See label
    MODE-OF-ACTION GROUP NAME (NUMBER1): Demethylation inhibitor (3)
    COMMENTS: Do not apply more than 8 fl oz/acre per crop. See label for maximum amounts allowed per season.
    H. FENBUCONAZOLE
    (Indar 2F) 6 oz 12 0
    MODE-OF-ACTION GROUP NAME (NUMBER1): Demethylation inhibitor (3)
    COMMENTS: Apply in a minimum of 20 gal water/acre. A protectant fungicide. Begin applications before infections occur if conditions are conducive to disease development. Do not apply more than 48 fl oz of product/acre per season.
    I. MYCLOBUTANIL
    (Rally 40WSP) 2.5–6 oz 24 0
    MODE-OF-ACTION GROUP NAME (NUMBER1): Demethylation inhibitor (3)
    COMMENTS: Do not apply more than 3.25 lb product/acre per season. More effective when applied as a concentrate (80-100 gal/acre) than as a dilute spray.
    J. TRIFLUMIZOLE
    (Procure 48SC) 10-16 fl oz 12 1
    MODE-OF-ACTION GROUP NAME (NUMBER1): Demethylation inhibitor (3)
    COMMENTS: Do not apply more than 96 oz/acre per season.
    K. FENARIMOL
    (Rubigan EC) 6–12 fl oz 12 0
    MODE-OF-ACTION GROUP NAME (NUMBER1): Demethylation inhibitor (3)
    COMMENTS: Do not apply more than 48 oz before harvest.
    L. METCONAZOLE
    (Quash) 4 oz 12 14
    MODE-OF-ACTION GROUP NAME (NUMBER1): Demethylation inhibitor (3)
    COMMENTS: Resistance to FRAC 3 group fungicide is low but possible in Monilinia populations. Use only when alternating with a fungicide that has a different FRAC Group number.
    M. IPRODIONE
    (Rovral 4) 1–2 pt 24
    MODE-OF-ACTION GROUP NAME (NUMBER1): Dicarboximide (2)
    COMMENTS: Addition of a narrow range oil (superior, supreme) at 1–2% increases the effectiveness of this material. Do not apply after petal fall.
    N. FENHEXAMID
    (Elevate 50WDG) 1.5 lb (stand alone),
    1–1.5 lb (tank mix)
    12 0
    MODE-OF-ACTION GROUP NAME (NUMBER1): Hydroxyanilide (17)
    COMMENTS: Do not apply more than 6 lb/acre per season or make more than 2 consecutive applications with this product.
    O. THIOPHANATE METHYL
    (Topsin M 70WP) 1.0–1.5 per 100 gal water 12 1
    MODE-OF-ACTION GROUP NAME (NUMBER1): Methyl benzimidazole (1)
    COMMENTS: Recommended rate is 1.5 lb/A. Use only once a year. Resistance to thiophanate methyl is common in populations of Monilinia fructicola and Botrytis cinerea in California cherry orchards. If resistance has occurred in the orchard, do not use this product. Otherwise, use only in combination or in an alternating application program with a fungicide that has a different Group number.
    P. PYRACLOSTROBIN/BOSCALID
    (Pristine) 10.5–14.5 oz 12 0
    MODE-OF-ACTION GROUP NAME (NUMBER1): Quinone outside inhibitor (11) and Succinate dehydrogenase inhibitors
    COMMENTS: To reduce the potential for the development of resistance, do not make more than a total of five applications per season of Group 7 or 11 fungicides.
    Q. AZOXYSTROBIN
    (Abound) 12–15.5 fl oz 4 0
    MODE-OF-ACTION GROUP NAME (NUMBER1): Quinone outside inhibitor (11)
    COMMENTS: Do not apply more than 1 lb a.i./acre per season.
    R. CAPTAN
    (Various 50WP) 4 lb 24 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.
    S. CHLOROTHALONIL
    (Echo 720) 3.125–4.125 pt 12 0
    (Bravo Ultrex) 2.8–3.8 lb 12 0
    (Bravo Weather Stik) 3.125– 4.125 pt 12 0
    MODE-OF-ACTION GROUP NAME (NUMBER1): Multi-site contact (M5)
    COMMENTS: May cause an allergic skin reaction in some people. Do not use with or closely following oil sprays. Do not apply more than 20.5 pt Bravo Weather Stik/acre per season. Do not apply more than 18.8 lb Bravo Ultrex/acre 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 fungicide with a different mode-of-action group number.
    Text Updated: 09/15
    Treatment Table Updated: 09/15