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Home > Horticulture > Chrysanthemum White Rust

Chrysanthemum White Rust Found in Maine

October 17, 2007

Chrysanthemum white rust (CWR), a quarantine significant pest, was found in Maine in October. Accidentally introduced to the United States several times in the past, CWR is not established in the US and when it is found, aggressive eradication efforts are implemented. This is the first find of CWR in Maine.

The infected plants in Maine were found at a retail chain store as part of a follow up from a supplier in New Jersey that had shipped potentially infected plant material. Federal officials have issued Emergency Action Notices to stop the infected plants from being sold and all infected plant material will be destroyed.

CWR only affect chrysanthemum and symptoms include light green to yellow spots on the upper surface of infected leaves that eventually turn brown. On the lower surface of the leaf buff to pink colored bumps (pustules) form that eventually turn white in color. Symptoms most commonly occur on leaves, but can also appear on flower bracts, petals and other green tissue.

If you believe you have a plant infected with CWR contact the Maine Department of Agriculture at (207)287-3891 or email Horticulture.

For more information:

USDA Chrysanthemum White Rust Information

British Columbia Ministry of Agriculture

University of Massachusetts Cooperative Extension

Chrysanthemum white rust symptoms on leaves