Chrysanthemum white rust

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Chrysanthemum white rust
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Scientific Classification
Kingdom: Fungi
Division: Basidiomycota
Class: Pucciniomycetes
Order: Pucciniales
Family: Pucciniaceae
Genus: Puccinia
Species: Puccinia horiana
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Areas where P. horiana has been confirmed (blue) and is unconfirmed (light blue)
White rust (English)

Rouille blanche (French)
Weisser chrysanthemenrost (German)

Roya blanca (Spanish)

Symptoms[edit | edit source]

Leaves[edit | edit source]

Following infection, pale-green to yellow spots, up to 5 mm in diameter, develop on the upper surface. The centres of these spots become brown and necrotic with aging. On the corresponding lower surface, raised, buff or pinkish, waxy pustules (telia) are found. As the spots on the upper surface become sunken, so these pustules become quite prominent and turn whitish when basidiospores are produced. Telia are occasionally found on the upper leaf surface. Severely attacked leaves wilt, hang down the stem and gradually dry up completely.[1]

Bracts and stems[edit | edit source]

Sori sometimes develop when crops are excessively affected.[1]

Flowers[edit | edit source]

Infection has been recorded as necrotic flecking with occasional pustules.[1][2]

Control[edit | edit source]

Preventive spraying with fungicides is effective but costly.[3] Active ingredients found useful include oxycarboxin, triforine, benodanil, triadimefon, diclobutrazol, dibitertanol and propiconazole. Some chrysanthemum cultivars are resistant and breeding for resistance continues.[4]

References[edit | edit source]


  1. a b c Data Sheets on Quarantine Pests - Puccinia horiana. European and Mediterranean Plant Protection Organization. Retrieved: 2011-01-30.
  2. Dickens, J.S.W. (1970) Infection of chrysanthemum flowers by white rust (Puccinia horiana). Plant Pathology 19, 122-124.
  3. Water, J.K. (1981) Chrysanthemum white rust. Bulletin OEPP/EPPO Bulletin 11, 239-242.
  4. Rademaker, W.; Jong, J. de (1985) [Japanese rust: how susceptible or resistant is the chrysanthemum?]. Vakblad voor de Bloemisterij 40, 49.