Country: United States

Title: Daylily Rust, Puccinia hemerocallidis

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Report:

Daylily rust, Puccinia hemerocallidis, was initially detected in the southeastern United States (AL, FL, GA, SC) in August 2000. As of January 2003, daylily rust was detected in 24 states (AL, AR, CA, CT, DE, FL, GA, HI, IN, LA, MD, MI, MN, MS, NJ, NC, OH, OR, PA, SC, TN, VA, and WI)*. 

Several "New Pest Advisory Group" (NPAG) conference calls were convened, involving Federal, State and university representatives. The following points were noted:

- Most of the foliage that may exhibit symptoms of infection is removed from the daylily tubers before shipment to the US, making it difficult to detect the fungus at ports-of-entry.
- It has been difficult to prevent the natural spread of daylily rust due to the number of airborne spores and short incubation period.
- Interstate movement of many susceptible daylily species, Patrinia species, and Hosta species is common practice. Daylilies are popular among hobbyists, and their movement is generally not regulated. 
- Few states have an effective quarantine in place. Many states that have daylily rust are not actively monitoring or applying mandatory control measures.
- There appear to be reasonably effective control measures (i.e., roguing and fungicides) used by producers. 

After reviewing all available information, we have determined that daylily rust is established and widespread in the US. A Federal quarantine is not a viable strategy to prevent further spread of the disease. Therefore, daylilies will not be prohibited from entering the US when daylily rust is detected at ports of entry, nor will a domestic quarantine be promulgated.

*July 3, 2003 UPDATE: It was incorrectly reported on 05/27/03 that daylily rust had been detected in Colorado. As of this date, daylily rust, Puccinia hemerocallidis, has not been detected in Colorado. 

Posted Date: May 27, 2003, 9 a.m.