Official Pest Report

Official Pest Reports are provided by National Plant Protection Organizations within the NAPPO region. These Pest Reports are intended to comply with the International Plant Protection Convention's Standard on Pest Reporting, endorsed by the Interim Commission on Phytosanitary Measures in March 2002.

Chrysanthemum White Rust (CWR): Limited Infestation in California

Country: United States

Title: Chrysanthemum White Rust (CWR): Limited Infestation in California

Not available


On December 1, 2004, Puccinia horiana, CWR, a pest of quarantine significance to the United States and regulated under CFR Title 7, 319.37-2, was suspected among growing plants of Dendranthema (florist’s mum) in a nursery in Carpenteria, Santa Barbara County, California by Santa Barbara County Plant Pathologist. 


The California Department of Food and Agriculture (CDFA) confirmed the presence of CWR on December 2.  On December 7, APHIS issued Emergency action notice (EAN) and began survey of the property on December 9.  On December 15, the destruction of affected plants was completed in addition to mandated fungicidal treatments required by the management plan.  A dooryard survey was conducted by CDFA and APHIS on December 16 with no findings of the disease in the environment.  On February 8, during a routine plant pest nursery survey, a Santa Barbara plant pathologist, again, discovered new pustules on the same property which were confirmed as CWR on December 2, 2004. Further inspections and regulatory treatments were conducted by Santa Barbara County Agriculture Officials, CDFA, and APHIS’ Plant Protection and Quarantine personnel. 


About 16,000 plants have been destroyed.  The actions required under the Santa Barbara County hold order, and the Federal EAN, inspections, and eradication efforts have been ongoing since the new discovery on February 8.  The infestation was considered limited in scope based on the number of infested plants detected.


The CWR management plan will be amended to deal with the problem of repeated sequential multiple infection in the same facility. 


Posted Date: April 7, 2005, 9 a.m.