Hollyhock: Rust

Biology

Hollyhock rust is caused by a fungus that overwinters in basal leaves which may live through the winter, or on plant debris. Spores remain viable for at least four months in the soil. Reddish, raised spots develop on leaf undersides, and then darken late in the growing season. Stems may also be attacked, and if the case is severe, leaves may dry up and hang down.

Management Options

Use Integrated Pest Management (IPM) for successful plant problem management.

Non-chemical Management

Select non-chemical management options as your first choice!

• Pick up and burn all infected plant parts during the growing season, at the end of the growing season, and again in early spring.
• Remove other hosts like cheeseweed (Malva parviflora), Lavatera, Hibiscus, and other Malvaceae plants.

Chemical Management

IMPORTANT: Visit Home and Garden Fact Sheets for more information on using pesticides.

• Fungicide applications should only be used in conjunction with cultural management options.

Approved Pesticides

Listed below are examples of pesticides that are legal in Washington. Always read and follow all label directions.

• Bonide Infuse Systemic Disease Control Lawn and Landscape
  Active ingredient: thiophanate methyl [EPA registration number: 53883-183-4]
• Hi-Yield Snake Eyes Dusting Wettable Sulfur
  Active ingredient: sulfur [EPA registration number: 7401-188-34911]
• Lilly Miller Sulfur Dust Fungicide/Insecticide Dust or Spray
  Active ingredient: sulfur [EPA registration number: 802-16]
• Spectracide IMMUNOX Multi-Purpose Fungicide Spray Concentrate
  Active ingredient: myclobutanil [EPA registration number: 9688-123-8845]
• This list may not include all products registered for this use.

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