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Researchers Identify Daylily Threat
November 6, 2002
Daylilies are one of the most popular perennials grown in the
United States. They are pretty, easy to grow and relatively low-maintenance.
But something began attacking U.S. and Costa Rican daylilies within the past
two years--a fungus that had never before been seen in the Americas. It was
first reported in Georgia during the summer of 2000 and has since spread to at
least 20 other U.S. states.
For a time, scientists weren't sure what this threat was. They
knew it resembled a species of fungus found on daylilies in eastern Asia, but
they didn't have enough hard evidence to identify it conclusively. Now,
however, researchers with the Agricultural Research Service's Systematic Botany
and Mycology Laboratory (SBML) in
Beltsville, Md., have proof that the fungus attacking American daylilies is an
Puccinia hemerocallidis, the fungal culprit, was first
described in Siberia and has also been reported in the Far East. It is a type
of rust fungus, a group so named because of the rusty-colored spots, ranging
from yellow to orange to dark-brown to black, that form on infected plants.
When scientists in the United States first began working to
identify the fungus attacking U.S. and Costa Rican daylilies, they did not have
a modern description or illustrations of P. hemerocallidisto to consult.
Mycology researchers at SBML, including José Hernández and Lisa
Castlebury, as well as Mary Palm, a mycologist for the
U.S. Department of Agriculture's
Animal and Plant Health Inspection
Service stationed at SMBL, have since rectified that situation.
They compared American daylily rust specimens with samples
collected in China, Japan, Russia and Taiwan. Their study included both
microscopic examination and DNA sequencing. Although variations existed between
samples, the researchers found that all of the specimens were of the same
Read more about their findings--and who will benefit from
them--in the November
issue of Agricultural Research magazine.
ARS is the USDA's chief scientific research agency.