Over the past 15 years, an invasive plant disease has left a patchwork of dead and dying trees in California's majestic coastal forests. But the loss of trees is changing more than just panoramic views: The number of ticks that can carry a disease that causes painful joint swelling, fatigue and even neurological damage is growing - a result of the gaps created in the forest when trees die, a recent study found.
To determine how the loss of trees affects ticks, their hosts and the Lyme disease they might carry, researchers at UC Berkeley, UC Santa Barbara and the Cary Institute of Ecosystem Studies in New York have embarked on a multi-year study of animal populations in a North San Francisco Bay forest infected with Sudden Oak Death.
read more in the San Jose Mercury-News
Monday, December 20, 2010
Monday, December 13, 2010
Oregon oak disease fight faces federal aid loss
BROOKINGS, Ore. (AP) — In 2001, U.S. Forest Service plant pathologist Ellen Goheen took to the air to see if sudden oak death was in Oregon.
The disease, which in two years can kill an otherwise healthy oak tree, earlier that year was identified as the causal agent killing huge swaths of oak trees in northern California.
The leading edge of the infestation was more than 100 miles from the Oregon-California border, but Goheen thought it possible that sudden oak death had entered Curry County.
Moments after starting her aerial survey, Goheen's suspicions were realized.
"The 'oh, shoot' factor was pretty high," she said.
Her discovery set off what has become a decade-long, $10 million battle with the fungal disease that threatens much of the West's timber and nursery industries.
http://www.necn.com/12/07/10/Oregon-oak-disease-fight-faces-federal-a/landing_health.html?&blockID=3&apID=5150b7d10ce24702947c0dc2d42fdbb2
The disease, which in two years can kill an otherwise healthy oak tree, earlier that year was identified as the causal agent killing huge swaths of oak trees in northern California.
The leading edge of the infestation was more than 100 miles from the Oregon-California border, but Goheen thought it possible that sudden oak death had entered Curry County.
Moments after starting her aerial survey, Goheen's suspicions were realized.
"The 'oh, shoot' factor was pretty high," she said.
Her discovery set off what has become a decade-long, $10 million battle with the fungal disease that threatens much of the West's timber and nursery industries.
http://www.necn.com/12/07/10/Oregon-oak-disease-fight-faces-federal-a/landing_health.html?&blockID=3&apID=5150b7d10ce24702947c0dc2d42fdbb2
More global trade means more forest pests
Along with U.S. manufacturing jobs, you can count another victim of global trade: American trees.
The most destructive forest pests from abroad are arriving at an accelerated pace, according to a new study. Between 1990 and 2006, new ones were discovered in the U.S. at an average rate of 1.2 per year, or nearly three times the detection rate during the previous 130 years.
The jump coincides with a rise in imports, leading the authors of a paper published in the December issue of BioScience to conclude that current rules and inspections to keep forest pests out of the country aren't that effective.
http://latimesblogs.latimes.com/greenspace/2010/12/foreign-forest-pests-on-the-rise-.html
The most destructive forest pests from abroad are arriving at an accelerated pace, according to a new study. Between 1990 and 2006, new ones were discovered in the U.S. at an average rate of 1.2 per year, or nearly three times the detection rate during the previous 130 years.
The jump coincides with a rise in imports, leading the authors of a paper published in the December issue of BioScience to conclude that current rules and inspections to keep forest pests out of the country aren't that effective.
http://latimesblogs.latimes.com/greenspace/2010/12/foreign-forest-pests-on-the-rise-.html
Public Concern About Invasive Tree Killing Insects and Diseases Remains Strong
Poll results indicate most Americans are concerned about non-native forest pests and they support measures to stop their spread
ARLINGTON, Va., Dec. 8, 2010 /PRNewswire-USNewswire/ -- Most Americans live near trees, and consider them very important to their quality of life. Recent polling by The Nature Conservancy shows that the American public is well aware of invasive forest pests that kill trees, and are willing to take steps to protect trees from this threat. According to the poll, conducted in September, knowledge of the spread of forest pests such as the Asian longhorned beetle and emerald ash borer, and of diseases like sudden oak death and thousand cankers disease, has increased by 13 percent, from 41 percent in 2005 to 54 percent in 2010. When asked about the issue of forest pests in the most general terms, 93 percent of poll respondents expressed concern. This high level of concern has not changed since 2005, despite the changing economic situation.
http://www.prnewswire.com/news-releases/public-concern-about-invasive-tree-killing-insects-and-diseases-remains-strong-111535019.html
ARLINGTON, Va., Dec. 8, 2010 /PRNewswire-USNewswire/ -- Most Americans live near trees, and consider them very important to their quality of life. Recent polling by The Nature Conservancy shows that the American public is well aware of invasive forest pests that kill trees, and are willing to take steps to protect trees from this threat. According to the poll, conducted in September, knowledge of the spread of forest pests such as the Asian longhorned beetle and emerald ash borer, and of diseases like sudden oak death and thousand cankers disease, has increased by 13 percent, from 41 percent in 2005 to 54 percent in 2010. When asked about the issue of forest pests in the most general terms, 93 percent of poll respondents expressed concern. This high level of concern has not changed since 2005, despite the changing economic situation.
http://www.prnewswire.com/news-releases/public-concern-about-invasive-tree-killing-insects-and-diseases-remains-strong-111535019.html
Massive gene loss linked to pathogen's stealthy plant-dependent lifestyle
An international team of scientists, which includes researchers from Virginia Tech, has cracked the genetic code of a plant pathogen that causes downy mildew disease. Downy mildews are a widespread class of destructive diseases that cause major losses to crops as diverse as maize, grapes, and lettuce. The paper describing the genome sequence of the downy mildew pathogen Hyaloperonospora arabidopsidis, which attacks the widely studied model plant Arabidopsis thaliana, is the cover story of this week's edition of the journal Science.
In the paper, the sequence of H. arabidopsidis is compared with other fully sequenced genomes of destructive plant pathogens to shed light on the differences in the ways microbes interact with their host and how those differences evolve. The payoff could be new ways to investigate how these pathogens wreak havoc and, in the long-term, finding how to prevent billions of dollars of losses for farmers growing crops across the globe.
http://www.eurekalert.org/pub_releases/2010-12/vt-mgl120610.php
In the paper, the sequence of H. arabidopsidis is compared with other fully sequenced genomes of destructive plant pathogens to shed light on the differences in the ways microbes interact with their host and how those differences evolve. The payoff could be new ways to investigate how these pathogens wreak havoc and, in the long-term, finding how to prevent billions of dollars of losses for farmers growing crops across the globe.
http://www.eurekalert.org/pub_releases/2010-12/vt-mgl120610.php
Tuesday, December 7, 2010
Characterizing Douglas-fir Tissue Colonization by the 'Sudden Oak Death' Pathogen, Phytophthora ramorum.
Characterizing Douglas-fir Tissue Colonization by the 'Sudden Oak Death' Pathogen, Phytophthora ramorum.
By Kathleen McKeever, M.S. and Dr. Gary Chastagner; Department of Plant Pathology, Washington State University Puyallup Research and Extension Center.
In 2001, Koch's Postulates confirmed Douglas-fir as a host for P. ramorum. Naturally-infected saplings have been observed in California forests, and studies on artificially inoculated Douglas-fir stems and shoots have established susceptibility parameters. Although naturally occurring stem infections in the U.S. have been limited to smaller diameter seedlings and saplings, P. ramorum stem cankers were recently observed on 8-year-old plantation grown Douglas-fir in Great Britain in 2009. All previous research has served to substantiate the importance of performing studies to characterize the behavior of P. ramorum in Douglas-fir and assess the potential risk that this pathogen poses to Douglas-fir ecosystems.
Artificial inoculation experiments were carried out to provide a thorough analysis of the colonization of Douglas-fir by P. ramorum. Goals of this research included determining which tissues are colonized by the pathogen, whether woody tissues are able to support sporulation, the likelihood of stem infections occurring on Douglas-fir with intact bark, and the viability of the pathogen in foliage. Methods employed included isolation, ELISA, and histological examination of stem tissues; qPCR and isolation to determine colonization efficacy and viability of the pathogen in needle tissues; and baiting studies to determine the ability of Douglas-fir bark to inhibit colonization of Rhododendron leaves by the pathogen.
ELISA results showed that proteins of the pathogen were detectable in the phloem, cambium, and superficial xylem, with infrequent detection in asymptomatic tissues. The pathogen was able to be isolated from all symptomatic woody tissues tested, but not from non-discolored tissues. ELISA and isolation techniques produced results that were highly positively correlated (r2=0.62, p=0.78), and histological observations paralleled information derived from these techniques. Douglas-fir bark reduced infection on Rhododendron leaf baits by up to 83 percent in the presence of inoculum. Results from foliage inoculations indicated that pathogen DNA is detectable using qPCR methods, but there was an inability to isolate the pathogen from needle tissue. Evidence of spore formation in woody stem tissues has not been observed.
It was concluded that the pathogen may be able to infect into the shallow xylem tissues of Douglas-fir in the presence of wounding, but there was no evidence of sporulation in tissues. The inability to isolate the pathogen from non-discolored tissues suggests that the proteins detected by ELISA outside of the lesion may be elicitins that are secreted in advance of hyphal colonization. The inability to isolate the pathogen from colonized needles may indicate the presence of chemical inhibitors that render the pathogen non-viable subsequent to initial infection. Finally, the ability of Douglas-fir bark to suppress infection of Rhododendron leaf baits suggests that the bark is inhibitory to P. ramorum and that infection of woody stem tissues through intact bark may be limited. Further research is required to identify the nature of this inhibition.
Characterization of P. ramorum colonization of Douglas-fir tissues is relevant to our current understanding of the behavior of the pathogen in different hosts and may enhance our ability to assess risk and create adequate regulations to thwart the spread of this exotic pathogen.
from the December COMTF newsletter
By Kathleen McKeever, M.S. and Dr. Gary Chastagner; Department of Plant Pathology, Washington State University Puyallup Research and Extension Center.
In 2001, Koch's Postulates confirmed Douglas-fir as a host for P. ramorum. Naturally-infected saplings have been observed in California forests, and studies on artificially inoculated Douglas-fir stems and shoots have established susceptibility parameters. Although naturally occurring stem infections in the U.S. have been limited to smaller diameter seedlings and saplings, P. ramorum stem cankers were recently observed on 8-year-old plantation grown Douglas-fir in Great Britain in 2009. All previous research has served to substantiate the importance of performing studies to characterize the behavior of P. ramorum in Douglas-fir and assess the potential risk that this pathogen poses to Douglas-fir ecosystems.
Artificial inoculation experiments were carried out to provide a thorough analysis of the colonization of Douglas-fir by P. ramorum. Goals of this research included determining which tissues are colonized by the pathogen, whether woody tissues are able to support sporulation, the likelihood of stem infections occurring on Douglas-fir with intact bark, and the viability of the pathogen in foliage. Methods employed included isolation, ELISA, and histological examination of stem tissues; qPCR and isolation to determine colonization efficacy and viability of the pathogen in needle tissues; and baiting studies to determine the ability of Douglas-fir bark to inhibit colonization of Rhododendron leaves by the pathogen.
ELISA results showed that proteins of the pathogen were detectable in the phloem, cambium, and superficial xylem, with infrequent detection in asymptomatic tissues. The pathogen was able to be isolated from all symptomatic woody tissues tested, but not from non-discolored tissues. ELISA and isolation techniques produced results that were highly positively correlated (r2=0.62, p=0.78), and histological observations paralleled information derived from these techniques. Douglas-fir bark reduced infection on Rhododendron leaf baits by up to 83 percent in the presence of inoculum. Results from foliage inoculations indicated that pathogen DNA is detectable using qPCR methods, but there was an inability to isolate the pathogen from needle tissue. Evidence of spore formation in woody stem tissues has not been observed.
It was concluded that the pathogen may be able to infect into the shallow xylem tissues of Douglas-fir in the presence of wounding, but there was no evidence of sporulation in tissues. The inability to isolate the pathogen from non-discolored tissues suggests that the proteins detected by ELISA outside of the lesion may be elicitins that are secreted in advance of hyphal colonization. The inability to isolate the pathogen from colonized needles may indicate the presence of chemical inhibitors that render the pathogen non-viable subsequent to initial infection. Finally, the ability of Douglas-fir bark to suppress infection of Rhododendron leaf baits suggests that the bark is inhibitory to P. ramorum and that infection of woody stem tissues through intact bark may be limited. Further research is required to identify the nature of this inhibition.
Characterization of P. ramorum colonization of Douglas-fir tissues is relevant to our current understanding of the behavior of the pathogen in different hosts and may enhance our ability to assess risk and create adequate regulations to thwart the spread of this exotic pathogen.
from the December COMTF newsletter
Soil positive for P. ramorum in WA
A Gig Harbor, Pierce County, WA landscape site adjacent to a previously positive repeat nursery has been found to have P. ramorum-positive soil. The confirmed site is along a drainage that had been found positive with infected salal plants in the summer of 2009. Soil sampling has been ongoing since the initial confirmation; however, this is the first time a positive sample has been recovered. The nursery associated with the site closed in August 2010, yet the retention ponds and outlet for the ponds continue to be positive for the pathogen. The nursery site is currently up for sale. The county has volunteered to remove the remaining host plants and material on the drainage banks where the previous salal find was confirmed in an effort to eliminate the pathogen's ability to become established. Survey work will also continue in the area. For more information, contact Michael Schell at michael.r.schell@aphis.usda.gov.
From the December COMTF newsletter
From the December COMTF newsletter
New research on mating hormone for control of P. infestans
ScienceDaily (Nov. 17, 2010) — Scientists are reporting a key advance toward development of a way to combat the terrible plant diseases that caused the Irish potato famine and still inflict billions of dollars of damage to crops each year around the world. Their study appears in ACS' journal Organic Letters.
Read the whole article at Science Daily
Read the whole article at Science Daily
Battle against Sudden Oak Disease tough, but essential
As you may have read in the Curry Coastal Pilot, the Oregon Board of Forestry recently met in Brookings and toured areas affected by Sudden Oak Death (SOD), the tree disease caused by the non-native pathogen Phytophthora ramorum. SOD is a relatively new disease to Oregon. Since its discovery in the Brookings area in 2001, forest managers in the public and private sectors have been working together to locate infected trees, eradicate the pathogen from infested sites, and slow the spread of the disease.
Cutting and burning infected and nearby trees may seem crude but it is the best disease management tool available to us. There is nothing we can spray to kill the pathogen or prevent trees from becoming infected. Cutting and burning infected trees, many of them still green, destroys the pathogen and reduces the potential for spread of air-borne spores. Unfortunately, it doesn’t always work as planned. Inconsistent funding often has delayed treatment and allowed the disease to spread before we can destroy it.
http://www.currypilot.com/20101124116570/Opinion/Public-Forums/Battle-against-Sudden-Oak-Disease-tough-but-essential
Cutting and burning infected and nearby trees may seem crude but it is the best disease management tool available to us. There is nothing we can spray to kill the pathogen or prevent trees from becoming infected. Cutting and burning infected trees, many of them still green, destroys the pathogen and reduces the potential for spread of air-borne spores. Unfortunately, it doesn’t always work as planned. Inconsistent funding often has delayed treatment and allowed the disease to spread before we can destroy it.
http://www.currypilot.com/20101124116570/Opinion/Public-Forums/Battle-against-Sudden-Oak-Disease-tough-but-essential
Plant disease threatens traditions of California tribes
From 2009:
Mary Larson Bishop gazes at the folds and peaks of the Santa Lucia Range with longing. "I used to go deep into the woods looking for herbs," says the Salinan tribal elder, who is known for her knowledge of medicinal plants such as yerba santa, traditionally used to heal skin inflammation. Now, she no longer roams the Central California coastal hills. "I'm afraid of bringing anything out of the woods that might spread to other trees," says Bishop. "I don't want to track that crud out of the hills."
The "crud" is Phytophthora ramorum, a minuscule waterborne mold that weakens and kills many species of native trees and plants. The pathogen, which causes both Sudden Oak Death and Ramorum blight, was first discovered in the mid-1990s. Since then, it has spread to 14 California counties along the Pacific Coast, and even to Washington and Oregon. It travels by clinging to boots, hands, pant legs and tires.
http://www.hcn.org/issues/41.12/cultural-blight
Mary Larson Bishop gazes at the folds and peaks of the Santa Lucia Range with longing. "I used to go deep into the woods looking for herbs," says the Salinan tribal elder, who is known for her knowledge of medicinal plants such as yerba santa, traditionally used to heal skin inflammation. Now, she no longer roams the Central California coastal hills. "I'm afraid of bringing anything out of the woods that might spread to other trees," says Bishop. "I don't want to track that crud out of the hills."
The "crud" is Phytophthora ramorum, a minuscule waterborne mold that weakens and kills many species of native trees and plants. The pathogen, which causes both Sudden Oak Death and Ramorum blight, was first discovered in the mid-1990s. Since then, it has spread to 14 California counties along the Pacific Coast, and even to Washington and Oregon. It travels by clinging to boots, hands, pant legs and tires.
http://www.hcn.org/issues/41.12/cultural-blight
Deadly P lateralis tree disease found at Loch Lomond
A deadly tree disease never seen in Britain before has been detected on the shores of Loch Lomond.
P. lateralis is a close relative of P. ramorum and is a root pathogen on Port Orford Cedar.
Read the rest of the article here:
http://www.bbc.co.uk/news/uk-scotland-11879891
P. lateralis is a close relative of P. ramorum and is a root pathogen on Port Orford Cedar.
Read the rest of the article here:
http://www.bbc.co.uk/news/uk-scotland-11879891
OAN makes case to Oregon congressional delegation for action during lame duck session
OAN supports funding continued efforts to contain and control Phytophthora ramorum, the pathogen that causes sudden oak death. Additionally, our delegation must pressure USDA not to implement its damaging and discriminatory prenofitication rule, requiring all nurseries to notify receiving states of host material shipped from Oregon.
http://oangovernmentrelations.blogspot.com/2010/12/oan-makes-case-to-oregon-congressional.html
http://oangovernmentrelations.blogspot.com/2010/12/oan-makes-case-to-oregon-congressional.html
Subscribe to:
Posts (Atom)