On February 14, 2007, the California Department of Food and Agriculture (CDFA) confirmed the detection of Chrysanthemum White Rust (CWR), Puccinia horiana P. Henn., on outdoor, ground-planted chrysanthemums at a cut flower nursery in San Diego County, California.
The CWR detection in San Diego County represents the third such occurrence of this disease at that particular production site; previously, CWR-positive findings also occurred there in 1998 and 2002. As a result of this latest detection, USDA issued an Emergency Action Notice (EAN) on February 16, 2007. Approximately 4,000 of the nursery’s chrysanthemum plants were pulled and bagged for burial at the local landfill.
In addition, on February 27, 2007, CDFA also made an initial detection of CWR in an outdoor field of mums at a cut flower nursery in Santa Barbara County, California. This detection was confirmed by CDFA and a USDA EAN was issued on March 1, 2007. Sizeable pustules consistent with CWR symptoms were visible among sprouted mums in the nursery’s tilled 1-acre field. Additional CWR-infected sprouts were detected following the initial finds in this field. This field had been harvested in mid-October to November 2006.
CDFA and USDA are following the National CWR Management Plan for Exclusion and Eradication in response to both detections in San Diego and Santa Barbara Counties. In both instances, the impacted nurseries only sold the product locally in California.