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steve hiker
03-17-2004, 21:54
Thursday, March 11, 2004 (SF Chronicle)
Nursery reports oak disease
Infested plants have been sold out of state -- scientists shocked

Peter Fimrite, Chronicle Staff Writer

Ornamental plants in the largest nursery in California -- a place that
distributes flora around the country -- have been infested with spores from
the tree-killing disease known as sudden oak death, it was revealed
Wednesday.

The discovery of Phytophthora ramorum in camellias at Monrovia Growers in
Azusa (Los Angeles County) means that the highly contagious disease has been transported to other states and may have been introduced into highly
susceptible oak forests in places like the southeastern United States.

The news hit like an earthquake as forest pathologists from around the
world gathered Wednesday at Sonoma State University for a California Oak
Mortality Task Force meeting.

Steve Oak, a forest pathologist for the North Carolina office of the U.S. Forest Service, said a great many of Monrovia's plants are shipped to the southeast, including places near the southern Appalachian Mountains, where Northern red oak trees make up 80 percent of the forest canopy in some places.

"We have a pathway that was theoretical before, but now is likely," he said during a break in Wednesday's conference. "The threat is very real."

It is especially troubling in that region because the oaks have replaced
the forests of American chestnut trees killed in one of the worst blights in world history. The chestnut blight, first discovered in 1904, killed some 3.5 billion trees in 50 years, essentially wiping out the entire species.

"It's a huge nursery with thousands of plants that went all over the
place," said Susan Frankel, a U.S. Forest Service plant pathologist who is
working with the state Department of Food and Agriculture on the problem.
"Hundreds of nurseries are now going to require inspections. Hundreds of
thousands of plants will have to be destroyed. We're very concerned for the
forests of the United States, for the nursery industry and trade. It's
terrible."

The news of yet another infestation was a major setback after two years
of progress fighting the fungus-like scourge that has killed tens of
thousands of California's majestic oaks. The widening swath of destruction
seemed to have slowed in the past two years, especially in the Bay Area, and
an effective phosphite treatment was developed and approved for use on
private trees.

But there were signs of trouble last year when Phytophthora ramorum,
which is the scientific name for the disease, was discovered in camellias in
a small nursery in Washington.

It meant the disease had spread to another state -- but infestations had
been found before in nurseries and isolated, so it wasn't yet a disaster.
However, Frankel said, the camellias were eventually traced back to
Monrovia. Testing of plants there confirmed Monday that six varieties of
camellias were infected, the first such infestation in arid Southern
California.

The major concern is that the 500-acre nursery does $30 million annually
in out-of-state shipments, Frankel said, and many of the plants sent out
over the past year may have been infected. That means they may serve as
hosts and spread the disease to wildland areas.

Steve Lyle, spokesman for the California Department of Food and
Agriculture, said lab samples are being taken and analyzed to determine how
extensive the Monrovia infestation is. "Surveying is ongoing at other
nurseries in California as well to see if the fungus has spread even
further," Lyle said. Katie Bloome, the spokeswoman for Monrovia Growers,
said shipments of all plants that are susceptible to sudden oak death have
been halted and she is confident the problem can be eradicated. "We're
on top of it," she said.

Meanwhile, forest pathologists from the United Kingdom and the
Netherlands outlined during the conference how Phytophthora ramorum has
spread from nursery plants to forested areas. It seems to be especially
deadly for beech and red oak trees in Europe.

Curiously, the microbe in Europe -- which was recently also found in the
Pacific Northwest -- is a different mating type from the one that dominates
in the United States. Scientists are desperately trying to keep the two
types apart for fear that they will mate and create an even more virulent
form of sudden oak death.

smokymtnsteve
03-17-2004, 23:47
mass production requires mass consumption

welcome K-mart shoppers..and thank you for shopping at wal-mart.

screwysquirrel
03-18-2004, 02:05
Nothing like mass shipping by air to spread a disease either plant or human. Just a faster way to kill good ole mother earth.

smokymtnsteve
03-18-2004, 09:45
brave new world????

aldous huxley...

brave new world revisted.

steve hiker
08-10-2004, 23:43
Hikers spread the sudden oak death pathogen through uninfected forests. If or when this disease shows up in the Appalachian region, we may have to impose a moratorium on AT thru-hiking until a fix is developed.

http://www.newscientist.com/news/news.jsp?id=ns99996257

<TABLE cellSpacing=0 cellPadding=0 width=370 align=left border=0><TBODY><TR><TD align=left>Hikers help spread sudden oak death





</TD></TR><TR><TD class=space5 align=left></TD></TR><TR><TD align=left><SMALL class=blu>10:29 10 August 04</SMALL></TD></TR><TR><TD class=space5 align=left></TD></TR><TR><TD><SMALL class=blu></SMALL>

<SMALL class=blu>NewScientist.com news service</SMALL>

</TD></TR><TR><TD class=space8 align=left></TD></TR><TR><TD align=left>Researchers have confirmed suspicions that trail users such as hikers and mountain bikers are helping to spread a disease that is devastating California forests.


The researchers found the pathogen causing sudden oak death was prevalent along trails through otherwise uninfected forests, but almost absent in soil samples taken two metres away from the trail.

They also found that the disease was more widespread in parks heavily used for hiking, mountain biking and horse riding than in less-visited areas. Previous work has shown that people can carry the pathogen on their shoes, but this is the first study to provide evidence of the consequences.

"Humans are moving the pathogen around, and the result seems to be higher levels of the disease," says J Hall Cushman, a biologist at Sonoma State University in California. He presented the data, collected over the last two years, at the Ecological Society of America conference in Portland, Oregon last week.


Difficult questions


Sudden oak death, caused by the fungus-like pathogen Phytopthora ramorum, is sweeping through forests in coastal California. It has also been detected in the UK and several other European countries.

The pathogen kills some oak species, and causes a non-fatal leaf disease in many other plants such as rhododendrons and California bay. Researchers suspect the disease is also spread by water and by other animals.

Cushman says the results pose difficult questions for land managers in California, where outdoor recreation is hugely popular. If managers do nothing, they may be criticised for not preventing the spread the disease.

Restricting trail access during wet seasons, when the pathogen is most active, would probably be most effective, but would also be unpopular and hard to enforce.

Another possible control method is to ensure visitors clean their shoes and bike tires before and after visits. The National Park Service plans to test this method this winter.


Wild fires

The need for action was highlighted by another study presented at the same conference. This predicted that in heavily infected areas the disease will kill up to up to 69% of a dominant native tree species, coast live oak (Quercus agrifolia), within five years.

<TABLE cellSpacing=0 cellPadding=0 width=370 align=left border=0><TBODY><TR><TD align=left>A dramatic protective measure against the disease was revealed in a third study presented at the conference – wildfires. "We almost never see infections in areas that burned" since 1950, says Max Moritz of the University of California, Berkeley.



Periodic wildfires are natural occurrences, but managers have historically suppressed them. Researchers are now working to discover why fires should have such a long-lasting effect.

The news that people and fire affect the spread of sudden oak death matches the experience of Patrick Robards, a ranger at China Camp State Park. The park is a notorious hotspot for sudden oak death that gets 300,000 visitors a year.

Robards conducted controlled burns as part of the park management regime, but stopped in 1999 due to lack of funds. He estimates that in burned areas fewer than 5% of oaks show signs of the disease - in areas that did not burn, up to 90% of oaks are dying or already dead.



</TD></TR><TR><TD class=space8 align=left></TD></TR><TR><TD>Mike Faden, Portland





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