Re: some news on sudden oak death plaguing the SF Bay Area
- To: Peter and Margaret Moir
- Subject: Re: some news on sudden oak death plaguing the SF Bay Area
- From: W* B*
- Date: Sat, 10 Mar 2001 10:35:56 -0800 (PST)
Yes, this was mentioned in a talk to the California Native Plant Society,
East Bay Chapter in Berkeley, Calif. Along with pictures of completely
dead forests of eucalyptus from a similar fungus/algae.
Elly Bade
Berkeley, California
On Sat, 10 Mar 2001, Peter and Margaret Moir wrote:
> What a pity there doesn't seem to be more international link-up between
> botanists or plant pathologists or whatever. Here in Western Australia we've
> been using phosphonate or phosphonic acid for the phytophthora infecting our
> native plants for quite a number of years. More and more uses are found for
> it all the time, and it's a comparatively benign fungicide I believe.
> Margaret Moir
> Olive Hill Farm
> Margaret River, Western Australia.
> www.wn.com.au/olivehill
> ----- Original Message -----
> From: Sean A. O'Hara <sean.ohara@groupmail.com>
> To: <medit-plants@ucdavis.edu>
> Sent: Saturday, March 10, 2001 6:09 AM
> Subject: some news on sudden oak death plaguing the SF Bay Area
>
>
> > The following was posted to the CA-Natives listserv this morning. Good
> > news about this horrible problem that has been sweeping through parts of
> > California.
> >
> > Sean O.
> >
> > March 9, 2001
> > By MARY CALLAHAN
> > THE PRESS DEMOCRAT
> > In the first promising news since scientists began tracking the deaths
> > of tens of thousands of Northern California oaks in 1995, researchers in
> > Sonoma County have identified a potential treatment.
> > Testing over the past seven months indicates a substance used to combat
> > a fungus in avocado trees also helps infected oaks, UC Berkeley
> pathologist
> > Matteo Garbelotto said.
> > "This is just a basic first step," Garbelotto said Thursday. "It's not
> > like we have a cure. But it's a first step that is really significant
> > because it's going in the right direction."
> > Garbelotto will present his findings today at a conference on sudden
> oak
> > death in Marin County, which is considered ground zero for the pathogen
> now
> > known to affect coast live oak, black oak, Shreve's oak and tan oak, as
> > well as California huckleberry and rhododendrons.
> > The fungus, called a Phytophthora, is related to the species that
> caused
> > Ireland's 19th century potato famine. It has been found in trees from Big
> > Sur to Sonoma County, and as far inland as the Sonoma-Napa County border.
> > Just weeks after Garbelotto and a UC Davis scientist isolated and
> > identified the pathogen that's been killing oaks for a half-dozen years,
> > Garbelotto and a team of researchers started experimenting with potential
> > treatments in Petaluma.
> > They applied four substances, including a water-based control substance,
> to
> > 90 potted trees infected with the sudden oak death fungus, he said.
> > The most successful, a phosphorus- and potassium-based fertilizer
> called
> > Phosphonate, reduced the size of cankers on the infected trees by an
> > average 75 percent, Garbelotto said.
> > "In terms of area, it was about a 15-fold reduction," he said.
> > Garbelotto said he chose to experiment with a fertilizer in part
> because
> > of its success with avocado trees and because the disease-causing pathogen
> > can't develop a resistance to it.
> > Phosphonate also lacks the toxic properties of a fungicide and "would
> > have better consequences for the environment," he said.
> > But it doesn't kill the microbe that causes sudden oak death. Instead
> it
> > contributes to the vigor of the tree and helping it battle the bleeding
> > lesions the fungus brings on.
> > A second chemical, used in the tests, a fungicide called Metalaxyl that
> > has been somewhat successful in treating potatoes, shows promise in
> > actually killing the fungus in the lab, Garbelotto said.
> > It reduced the size of lesions, too, though not as successfully as
> > Phosphonate.
> > Unfortunately, the oak fungus, if treated with Metalaxyl, could develop a
> > resistance that would render the fungicide ineffective, he said.
> > "It may be in the end a combination of the two may be the most
> effective
> > treatment," Garbelotto said.
> > Scientists will continue tests using the two substances, as well as
> > others, to pinpoint how they work -- and how they work best.
> > The federal government recently set aside $3.5 million for research,
> > monitoring and management efforts related to sudden oak death.
> > State and federal funds totaling $1.6 million already have been
> > allocated to help fight the disease.
> > The California Oak Mortality Task Force, formed last August, has
> > estimated $10 million is needed over the next two years.
> > Researchers tried several different applications for the recent
> > experiments, but injection so far works best and has fairly low
> > environmental impact because it delivers the chemical directly into the
> > tree, Garbelotto said.
> > The trees, tested at an undisclosed location in Petaluma under what
> > Garbelotto called "pretty rigorous conditions," were all about five to
> > seven years old, standing about 9 feet to 14 feet, he said.
> > By infecting the trees in August and then again in November,
> researchers
> > were able to simulate young and old cankers, he said.
> > Though the treatment worked best on the younger lesions, "we still got
> > significant control in the older cankers," Garbelotto said.
> > "That could be a good indication that the earlier we catch them, the
> > better," he said.
> >
> >
> > h o r t u l u s a p t u s - 'a garden suited to its purpose'
> > Sean A. O'Hara fax (707) 667-1173 sean.ohara@groupmail.com
> > 710 Jean Street, Oakland, CA 94610-1459, U.S.A.
> >
> >
>
>
