A New Pest Concern in New England:
Chrysanthemum White Rust
with updated images
October 2007

Chrysanthemum white rust (Puccinia horiana) was confirmed for the first time in Connecticut on September 12, 2007 in Fairfield and Hartford Counties.  Infected plants were found in nurseries and garden centers during visual inspections by Connecticut Agricultural Experiment Station staff.  The disease was confirmed by Sharon Douglas from the Experiment Station and a USDA APHIS laboratory.  The plants that tested positive last week for chrysanthemum white rust (CWR) were ‘Gretchen’ cultivars.  Although CWR has occasionally been reported in the U.S. and Canada, all previous outbreaks were eradicated successfully.  CWR is a regulated pest of quarantine significance, and steps are being taken by state and federal regulators to remove and destroy infected plants from the two confirmed sites.  Additional inspections are underway at nurseries and garden centers in Connecticut. 

Chrysanthemum white rust infects 12 species of chrysanthemum, including garden mums, pot mums, and Nippon daisies.  The disease was first found in Japan and China more than 100 years ago, and has since become established in Europe, South America, Central America, Africa, Australia and parts of Asia.  Infected plants may not show any symptoms of the fungus during hot or dry conditions until the weather turns cool and wet.  Symptoms of CWR on infected plants include raised pink or white pustules on the underside of the leaf and chlorotic spots on the upper leaf surface.  Severe outbreaks of CWR may result in total crop loss. 

Additional information is available via the following links: 

USDA - APHIS - Plant Health, Plant Protection and Quarantine
http://www.aphis.usda.gov/plant_health/plant_pest_info/cwr/index.shtml 

USDA, ARS Systemic Botany and Mycology Laboratory
http://nt.ars-grin.gov/taxadescriptions/factsheets/index.cfm?thisapp=pucciniahoriana

British Columbia Ministry of Agriculture Food and Fisheries
http://www.al.gov.bc.ca/cropprot/cwrust.htm 

 

Chrysanthemum White Rust - pustules.  Sharon M. Douglas image

click on image to see a larger view

Chrysanthemum White Rust - Plant damage.  Sharon M. Douglas image

click on image to see a larger view

images from:
Sharon M. Douglas, Ph.D., Plant Pathologist Head,
Department of Plant Pathology & Ecology
The Connecticut Agricultural Experiment Station
123 Huntington Street (zip code 06511)
P. O. Box 1106New Haven, CT  06504  USA

Donna Ellis
Extension Educator and State Survey Coordinator,
USDA APHIS Cooperative Agricultural Pest Survey (CAPS) Program
University of Connecticut
Department of Plant Science
1390 Storrs Road, Unit 4163
Storrs, CT  06269-4163
Phone (860) 486-6448
FAX (860) 486-0534

email donna.ellis@uconn.edu

 UConn Integrated Pest Management: www.hort.uconn.edu/ipm/

 

Information on our site was developed for conditions in the Northeast. Use in other geographical areas may be inappropriate.

The information in this material is for educational purposes. The recommendations contained are based on the best available knowledge at the time of printing. Any reference to commercial products, trade or brand names is for information only, and no endorsement or approval is intended. The Cooperative Extension system does not guarantee or warrant the standard of any product referenced or imply approval of the product to the exclusion of others which also may be available.All agrochemicals/pesticides listed are registered for suggested uses in accordance with federal and Connecticut state laws and regulations as of the date of printing. If the information does not agree with current labeling, follow the label instructions. The label is the law.Warning! Agrochemicals/pesticides are dangerous. Read and follow all instructions and safety precautions on labels. Carefully handle and store agrochemicals/pesticides in originally labeled containers immediately in a safe manner and place. Contact the Connecticut Department of Environmental Protection for current regulations.The user of this information assumes all risks for personal injury or property damage.Issued in furtherance of Cooperative Extension work, Acts of May 8 and June 30, 1914, in cooperation with the U.S. Department of Agriculture. Kirklyn M. Kerr, Director, Cooperative Extension System, The University of Connecticut, Storrs. The Connecticut Cooperative Extension System offers its programs to persons regardless of race, color, national origin, sex, age or disability and is an equal opportunity employer.

menu