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Rose Rust

Phragmidium sp.
Updated Oct 10, 2024
 
1

Make a Positive Identification

  • Rose rust is a fungus that mottles the upper surface of rose leaves.
  • It forms orange bumps (pustules) on the lower surface.
Species: Rose rust
Orange rust pustules on underside of leaves

Jay W. Pscheidt, Oregon State University

Look for orange spots (pustules) on the lower leaf surface.

Species: Rose rust
Orange pustule on rose flower bud

Orange pustules form on buds and stems.

Species: Rose rust
Underside of rose leaves in winter showing black fungal structures

William M. Brown Jr., Bugwood.org

Black fungal structures develop on the undersides of rust infected leaves during the winter. These structures make spores that spread rust the following spring.

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LOOK-ALIKES: BLACK SPOT AND DOWNY MILDEW
Species: Black Spot
Mottled green and yellow leaf with black spots. The spots have diffuse edges.

William Fountain, University of Kentucky, Bugwood.org

Rose black spot is a fungal disease. It causes black spots and blotches with diffuse edges on rose leaves. See How to Get Rid of Rose Black Spot

Species: Downy Mildew
Purple spots from downy mildew on rose leaf

Jean L. Williams-Woodward, University of Georgia, Bugwood.org

Downy mildew is a fungal leaf disease. It causes purple spots on the upper leaf surface. Downy mildew forms white structures on the bottom of leaves. See How to Get Rid of Rose Downy Mildew

 
2

Rose Rust Benefits

  • Rust is a plant disease that harms susceptible rose plants. It doesn’t have any benefit for people or the environment.
 

Rose Rust Risks

  • Rose rust impacts the way rose plants look.
  • It weakens plants and distorts growth.
  • It causes early leaf loss.

 

Risk Card
Does it cause harm?
Adults & Children
None
Property
Low
Pets
None
Annoyance
Some
Environment
None
Action Optional
 
3

TAKE ACTION?

Rose rust impacts the way rose plants look. Take action if you can’t tolerate the damage.

Do I need to take action?
If you don’t like how it looks, you can take action.

What if I do nothing?

  • Rose rust weakens plants.
  • Rose rust is the least serious of the common rose diseases. Black spot and rose powdery mildew are more harmful to roses.
 
4

PREVENT ROSE RUST

‘Just Joey’ rose bloom and healthy foliage
Plant Resistant Rose Varieties
  • Rust resistant rose varieties include ‘Electron’, ‘Just Joey’, ‘Tournament of Roses’, ‘Europeana’ and ‘Showbiz’, climber ‘Dublin Bay’, and Rosa rugosa varieties.
  • For more varieties, See Rose Cultivar Resistance   (PNW Plant Disease Management Handbook).
  • Disease resistant varieties may be available at nurseries and garden centers. Look on the plant tag or ask a store employee.
Roses in container at store

rcmirani, iStock

Don’t bring diseased roses into your garden
  • Inspect new rose shrubs for signs of disease before buying.
  • When planting rose bushes leave enough space between plants to ensure good airflow.
  • Prune established rose bushes to maximize airflow.
  • Plant roses in full sun.
 
5
HOW TO GET RID OF ROSE RUST

Prevention

  • For new rose plantings, choose varieties that are resistant to rust and other diseases. See Rose Cultivar Resistance  (PNW Plant Disease Management Handbook).
  • Don’t bring diseased roses into your garden.
  • Avoid overhead sprinklers. Irrigate early in the day to allow leaves to dry.
  • Prune established rose plantings to promote air flow. Good air flow reduces the conditions that favor plant diseases.

Non-chemical Methods

  • Remove stems, leaves, and flowers that show disease.
  • Rake up fallen leaves to disrupt the disease’s life cycle.

Chemical Methods

  • Fungicides effectively control rose rust when used according to the label instructions. Fungicides are pesticides that target fungal diseases on plants.
  • Check for application timing on the label. It may be hard to control rose rust once plants develop disease symptoms. 

NEED HELP?

Consider a licensed pest control company. Learn How to Hire a Pest Control Company.
Your local Extension Specialist in Oregon  and other states  can suggest other methods.

Jump to

Method Does it work? Is it safe? Recommendation
A
Sanitation: Pruning and Raking Leaves
Effective
Low risk
Recommended
B
Control with Fungicides
Effective
Moderate risk
Use if Necessary
C
If Using Fungicides, Protect Yourself & Minimize Risks
 
A

Sanitation: Pruning and Raking Leaves

Non-Chemical Method

"cobwebs" by anjollie123456 is licensed under CC BY-NC-ND 2.0

Sanitation: Pruning and Raking Leaves

Recommended

Raking fallen leaves and pruning to promote airflow disrupts the rust disease life cycle.

Does it work?
Effective

These non-chemical strategies help minimize rose disease problems.
How much effort?
Moderate effort
What's the risk?
Low risk
Possible risk of exposure or harm from chemicals
NONE
Loppers cutting a rose cane

Signe Danler, Oregon State University

Prune roses to promote airflow. Thin out and space canes to open up the center of the shrub. This helps the leaves dry quickly after rain to reduce disease pressure. Avoid overhead watering.

Gloved hand pulling infected leaves from rose bush

Signe Danler, Oregon State University

Remove stems, leaves, and flowers that show disease to limit the spread.

Raking diseased leaves into bag for disposal

Signe Danler, Oregon State University

Rake up and remove diseased leaves that fall to the ground.

Yard debris bin

Weston Miller, Oregon State University

Dispose of diseased material in your debris bin, compost pile, or burn pile.  Don’t use homemade compost that includes diseased rose material to amend the soil near your rose bushes.

 
B

Control with Fungicides

Chemical Method: Use with caution

iStock

Control with Fungicides

Use if Necessary
Does it work?
Effective

Fungicides effectively prevent rose rust when used according to label directions.
How much effort?
Moderate effort
What's the risk?
Moderate risk
Possible risk of exposure or harm from chemicals
El uso de fungicidas conlleva cierto grado de riesgo. El riesgo más bajo se produce sin el uso de fungicidas.

You may be exposed to a fungicide if you:

  • Get it on your skin
  • Breathe it in
  • Eat or smoke afterward without washing hands
  • Touch or eat plants that are wet with spray (you, pets, or children)
  • Bring it inside on your shoes or clothes

Follow directions closely to reduce risk.

Some products are available for home use. A few are listed below. These active ingredients are suggested chemical treatments to control rose rust. Look for these chemical names in the “Active Ingredients” section of product labels. Many fungicides used for black spot will be helpful to control rust.

  • Bacillus amyloliquifaciens strain D747
  • Mineral oil 
  • Neem oil Clarified hydrophobic extract (Some formulations are OMRI-listed for organic use.) 
  • Sulfur
  • Chlorothalonil
  • Copper fungicides

Suggested pesticides are from the Pesticide Information Center Online (PICOL) Database. They are permitted for HOME use in Oregon. Read the label for application directions and effectiveness information.

ONLY professional pesticide applicators can use Restricted-Use Pesticides (RUP) that may be more effective. If you need further support, contact a licensed pesticide applicator.

Example label with active ingredient neem oil

Sample product label with Active Ingredient(s) highlighted

A red box on the example label highlights active ingredient Clarified hydrophobic extract of Neem oil. The label lists rust.

Fungicide Application Tips

  • Proper timing of fungicide sprays is important for them to be effective against rose rust. 
  • Check for application timing on the label. It may be hard to control rose rust once plants develop disease symptoms.
  • Researchers recommend alternating products (by active ingredient). Local populations of rose rust may develop resistance if only one type of fungicide is used repeatedly.
  • Using fungicides comes with real risks. ALWAYS read the entire label front to back. Review instructions even for brands you know.
 

If Using Fungicides, Protect Yourself & Minimize Risks

Chemical Method: Use with Caution
Gloved hands holding fungicide package to read label

Weston Miller, Oregon State University

Why Is It Important to Read Fungicide Product Labels?

  • They have detailed information on how to use the product correctly and legally.
  • They contain information on potential hazards of the product.
  • They provide instructions you should follow for poisonings and spills.
  • Following label instructions helps you to minimize the risks and maximize the benefits.

Key Fungicide Safety Tips

  • Read the entire label front to back.
  • Follow the instructions.
  • Review the instructions even for brands you know.
  • Only apply the product where the label says it can be applied.
  • Keep all fungicides in their original container.

The Label is the Law

ALWAYS read the label before using fungicide products. The label is a legal document that provides information on how to safely use the fungicide. This helps avoid harm to human health and the environment. Using a fungicide in off-label ways is illegal. It can result in legal enforcement actions.

READ THE LABEL & Follow Instructions
It has instructions to protect you and the environment.

  • Labels are different for every product and they often change over time.
  • Use a magnifying glass for small print.
  • Pay attention to CAUTION, WARNING, and DANGER statements.
  • Pay attention to the PRECAUTIONARY STATEMENTS.
  • The law states you must read and follow fungicide instructions.

Protect Yourself
Eye, skin & lung irritants

  • Wear the correct personal protection equipment. The right gear often includes chemical-resistant gloves, safety glasses, a long-sleeve shirt, pants, socks, and shoes.
  • Mix fungicide products outdoors or in a well-ventilated area.
  • Wash hands after you mix or apply fungicides and before smoking or eating.
  • Wash clothes worn while mixing and applying fungicides separately from all other laundry.

Protect Children & Pets
Children and pets are at risk if they eat or touch the plant before fungicides dry.

  • Keep them away during and after applying fungicides (read label for how long).
  • Remove toys and pet dishes from yard before applying.
  • Don’t track fungicide products into home on shoes or clothes.

Protect Pollinators

  • Apply early morning or evening when bees are less active.
  • Avoid spraying flowering plants, if possible.
  • Don’t spray on bees or insects.

Storage & Disposal

  • Store out of the reach of children and pets.
  • Store in a cool and dry place.
  • Never pour down any drain.
  • If you mix too much, apply it rather than storing it.
  • Don’t put fungicide containers in the trash unless instructed by the label.
  • Take unused fungicides to a hazardous waste facility.

Call  1-800-CLEANUP (1-800-253-2687) to find out where to dispose of pesticides.

For the Portland metro region in Oregon, contact Metro’s Recycling Information. Call  503-234-3000, email   or visit Metro’s website  

More about:

About Using Pesticides on School Grounds in Oregon

If using pesticides on school grounds, there are special rules in Oregon. See School Integrated Pest Management  (Oregon Department of Agriculture).

NEED HELP?

The National Pesticide Information Center (NPIC)  can answer questions about pest control chemicals.
 1-800-858-7378 or npic@ace.orst.edu  

Consider using a licensed pest or weed control company. Learn How to Hire a Pest Control Company.

Your local Extension Specialist in Oregon  and other states  can suggest other methods.

SEE OTHER COMMON PACIFIC NORTHWEST INSECTS, SLUGS & DISEASES ON PLANTS

Content provided by editor Weston Miller and writers Signe Danler and Jeremiah Mann. Pesticide safety information edited by Kaci Buhl.

  Peer review facilitated by OSU Department of Horticulture.

Photo of Weston Miller

Weston Miller

Project Founder and Content Writer

Weston Miller served as Community and Urban Horticulture faculty for Oregon State University Extension Service for Clackamas, Multnomah, and Washington Counties. Weston is an author for content for this website. He developed funding partnerships with Portland area agencies to initiate and build out the Solve Pest Problems website focused on this goals:

Signe Danler

Signe Danler (Editor/Writer)

Signe Danler is a veteran Master Gardener and landscape designer, with an MAg degree in Horticulture from OSU, and an emphasis on Urban Horticulture. As instructor for the OSU Extension Service online Home Horticulture and Master Gardener Program, she uses her experience and training in gardening, urban forestry and ecological landscaping to communicate about and promote sustainable gardening and landscaping practices.

Photo of Kaci Buhl

Kaci Buhl

At the state level, I lead the Pesticide Safety Education Program (PSEP). The program hosts live recertification events around the state, serving over 1,000 licensed pesticide applicators each year. We also produce web-based training modules and license-preparation study manuals. Special training for unlicensed pesticide applicators is also available through a grant from the USDA Specialty Crop Block Grant Program. The PSEP at OSU works closely with the Oregon Department of Agriculture's Pesticides Division.

J. Jeremiah Mann

J. Jeremiah Mann

J. Jeremiah Mann completed a Physical Science undergraduate degree at Humboldt State University, and M.S, Ph.D focusing on plant science topics at UC Davis. He went on to work for the Natural Resources Conservation Service and in a leadership position serving a private agricultural technology company. He currently lives in Sacramento California where he consults on pest and property management topics.

Rose Rust References

Rose (Rosa spp.) and hybrids: Rust
PNW Pest Management Handbooks

Rose Rust in the Landscape
Penn State Extension

Controlling diseases and aphids on your roses  
OSU Extension Service Publication EC 1520

Rose Cultivar Resistance
PNW Pest Management Handbooks