A comprehensive resource about P. ramorum
 |
 |
 |
 |
 |
 |
 |
 |
 |
 |
 |
 |
BASIC FACTS ABOUT P. RAMORUM
What is P. ramorum?
How does P. ramorum impact plants?
What does P. ramorum look like?
Which plants can be affected?
Is P. ramorum preventable?
Where is P. ramorum found?
How is P. ramorum spread?
How can P. ramorum be controlled and eliminated?
P. RAMORUM IN OREGON
What is the situation in Oregon nurseries?
Have Christmas trees been affected by P. ramorum?
How has Oregon responded to this issue?
Is there a list of certified growers?
REGULATORY PROCESS
Is the federal government regulating this issue?
What are the next steps for federal regulation?
Is the state of Oregon regulating this issue?
Is there a list of certified growers in Oregon?
CONSUMER QUESTIONS
Should I be worried that plants I am buying are infected with P. ramorum?
If it can spread, what’s being done about it?
How do I know if my plants are infected?
How can I help prevent the spread of P. ramorum?
_____________________________________________________________________________________________________________
COMPLETE Q & A
BASIC FACTS ABOUT P. RAMORUM
What is P. ramorum?
Phytophthora ramorum (fi -TOFF- thora ram-OR-um) is a fungus-like organism that can cause leaf spotting, stem canker, or leaf blight on a variety of woody ornamentals. It can also kill several species of oak, such as tanbark oak and live oak very rapidly, hence its common name, sudden oak death. Even though for the vast majority of host plants, it is no more serious a pest than many of the other species of aerial Phytophthora, the nursery industry is taking the threat of P. ramorum very seriously.
The fungus does not harm animals or humans. Rather than call this disease sudden oak death, most experts are now calling this disease ramorum leaf spot, or ramorum die-back. Because it is not recognized as being widely distributed in the U.S., the USDA has established a quarantine against this organism.
P. ramorum prefers cool, damp weather and is suppressed by hot, dry weather, though it still can survive in these conditions. It can be spread by irrigation water, rain-splash and probably by blowing wind. Scientists have discovered two specific forms of this organism, a European form (A1) and a North American form (A2). The North American form has been shown through research to be generally less damaging and less prolific than its European cousin.
The genus Phytophthora is made up of many species in addition to P.ramorum. Other species, with habits similar to P. ramorum are common in the U.S. These are generally referred to as ‘aerial’ Phytophthora.
Back to "Basic Facts" questions
How does P. ramorum impact plants?
Symptoms vary by plant species and often resemble symptoms caused by other species of Phytophthora. Laboratory tests are required to make a diagnosis. For most host species, the symptoms range from leaf spots to twig lesions. Some plant species suffer a die-back of stems or branches. A few species of plants can be killed by the fungus, including tanbark oaks and some live oaks. It is generally confined to attacking above-ground parts of plants, and is rarely found in soil or associated with roots. Thus, it is considered an aerial Phytophthora (as opposed to being a root-rotting form of Phytophthora.) It can persist either as an active, vegetative infection, or as a dormant spore.
On some plants, including camellia, the fungus generally causes few symptoms, and it reproduces at a very low level. This combination of factors makes it difficult to detect on camellia and has thus set the unfortunate conditions that allowed the shipment of infected camellia plants to nurseries across the U.S.
Back to "Basic Facts" questions
What does P. ramorum look like?
The symptoms of the disease are often subtle and can be confused with infections of other fungi (including other species of leaf and stem-infecting Phytophthora), sunscald, frost damage, nutrient or soil problems and other natural causes. Symptoms alone do not mean a plant is infected. The only way to determine if a plant is infected is to have it tested by an experienced laboratory. In Oregon, those labs include the Oregon Department of Agriculture (503-986-4636) and the Oregon State University Plant Clinic (541-737-3472).
Below are some examples of infected plants (photos courtesy of the Oregon Department of Agriculture):
Infected Camellia showing leaf browning Infected Rhododendron leaf showing diffuse
and collapse browning around mid-vein
Additional pictures and descriptions of the fungus and its hosts also can be seen at the Diagnostic Guide link at: www.suddenoakdeath.org.
Back to "Basic Facts" questions
Which plants can be affected?
Any plant that is capable of being infected by a pathogen is called a host plant. It is important to note that all plants that are hosts (i.e. capable of being infected) are not necessarily infected with P. ramorum. P. ramorum only infects certain plants and the vast majority of plant species do not harbor P. ramorum.
Currently, there are 28 regulated host species listed by the USDA. An additional 36 species are suspected hosts, but conclusive scientific studies are not yet complete. All the species and crosses of the genus Rhododendron and Camellia are considered hosts. The following three genera have multiple host species: Pieris, Quercus and Viburnum. New hosts are being found almost monthly, however, most are minimally impacted from a disease standpoint.
For the most current list of hosts classified by the USDA, click here: http://www.aphis.usda.gov/ppq/ispm/sod/usdasodlist.html
Back to "Basic Facts" questions
Is P. ramorum preventable?
The best way to avoid infection by P. ramorum is to exclude the pathogen from a production facility or growing site. A panel of nursery stock growers, plant pathologists, consultants and regulators from California, Oregon and Washington met over the summer and fall of 2004 and have drafted a set of grower practices that will effectively prevent any new introductions to a production facility. By using a combination of these “best management practices” and effective regulations (which include a thorough inspection and testing program), high quality and healthy plants are assured.
Back to "Basic Facts" questions
Where is P. ramorum found?
Phytophthora ramorum was originally detected in Germany in 1993. A few years later, it was found in Marin County, California. It has been detected in the European Union, in Canada and in at least 21 states of the U.S including Alabama, Arizona, Arkansas, California, Colorado, Florida, Georgia, Louisiana, Maryland, New Jersey, New Mexico, New York, North Carolina, Oklahoma, Oregon, Pennsylvania, South Carolina, Texas, Tennessee, Virginia and Washington state.
Back to "Basic Facts" questions
How is P. ramorum spread?
Researchers are studying how P. ramorum spreads. The pathogen has been isolated from host debris (e.g. firewood and leaves), nursery stock, soil, stream water and rain-splash. Human movement of infested host materials is considered the most likely means of long distance spread. Infested soil and water-splash may contribute to local and/or tree-to-tree spread of the disease. Researchers are also investigating insects and birds as possible vectors for this disease.
Back to "Basic Facts" questions
How can P. ramorum be controlled and eliminated?
Once a plant is infected, there is no treatment for P. ramorum. Plants may be protected from the infection with labeled fungicides. The best way to protect plants from P. ramorum is to utilize specific best management practices that lower the risk of receiving infected material. Because it is a regulated disease, all infected plants must be incinerated to ash or subjected to deep burial (to a depth of a least 6 feet) and double plastic bagged.
Back to "Basic Facts" questions
P. RAMORUM IN OREGON
What is the situation in Oregon nurseries?
Oregon has participated in all annual surveys for Phytophthora ramorum since the inception of the USDA inspection program in 2001. To date, over 70,000 samples have been collected and processed in Oregon, and the pathogen has been detected to a very limited extent in a few nurseries. In these cases, the Oregon Department of Agriculture (ODA) took immediate action to suspend shipments and to intensively survey the nurseries and surrounding environs for the pathogen. The nurseries fully cooperated with state and federal authorities and provided all shipping documents necessary to conduct trace back and trace forward surveys.
Back to "P. ramorum in Oregon" questions
Have Christmas trees been
affected by P. ramorum?
To date, no Christmas trees in the Pacific Northwest have been found
infected with P. ramorum.
Christmas trees in Oregon have been intensively surveyed and not a
single infected tree has been found.
Back to
"P. ramorum in Oregon" questions
How has Oregon responded to this issue?
The Oregon Association of Nurseries asked the ODA to immediately
implement a Phytophthora ramorum-free nursery stock certification
program. This is a mandatory program for all
Oregon
nurseries that produce host material and requires annual testing and
inspection of the facility. In addition, all host and associated host
materials shipped into
Oregon
must either have been produced in a nursery with an ODA-approved
Phytophthora ramorum-free nursery stock certification program, or
the material must be safeguarded, segregated, held, inspected and tested
prior to release. This is a state-of-the-art program using the most
current sampling and testing procedures and will set the benchmark for
Phytophthora ramorum host stock production in the industry.
In Oregon,
the nursery industry members, their association and the state regulators
have always taken an aggressive stand with respect to Phytophthora
ramorum. We have constantly urged the USDA to add more resources
for survey efforts and to take a strong position with respect to
international and interstate shipments of high-risk stock. We believe
our aggressive response is directly related to the negligible level of
Phytophthora ramorum present in our state. However, we are
prepared to go further to assure customers and regulators that Oregon
offers high quality, Phytophthora ramorum-free nursery stock.
Back to
"P. ramorum in Oregon" questions
Is there a list
of certified growers?
The Oregon Department of Agriculture keeps an up-to-date list of
certified nurseries and Christmas tree growers.
Click here for a current list of certified growers.
Back to
"P. ramorum in Oregon" questions
REGULATORY PROCESS
Is the federal government regulating this issue?
On February 14, 2002, the
United States Department of Agricuture (USDA) published a quarantine
(Interim Rule Ch 7 CFR 301.92) that regulates the interstate movement of
P. ramorum hosts and associated hosts and other restricted
articles. The rule regulates quarantined areas of California and a small
area in southwest Oregon. The rule was modified by an
emergency order
issued on April 22, 2004, which increased the scope of the regulation to
include all of California. Another emergency order is under
consideration, which would include Oregon and Washington state.
Additional regulations will likely include parts of Canada and Europe
where P. ramorum is known to occur.
Back to "Regulatory
Process"
questions
What are the next steps for federal
regulation?
The USDA is currently reviewing and
amending the regulations for P ramorum. Part of the new rules
will include a new plant certification program, relying on individual
states to conduct official “state nursery stock cleanliness programs” (SNSCPs).
These programs must meet all the conditions and requirements of the
federal quarantine, and be approved by the USDA. Oregon, through its
industry-supported and mandatory 100% inspection program, serves as a
model for this new approach and is uniquely qualified to become the
first state to pursue a SNSCP. Through partnerships with Oregon State
University and the USDA ARS, production methods will be developed,
tested and verified. These methods will provide peer-reviewed and
scientific evaluation of the SNSCP and help drive its successful
implementation.
Back to "Regulatory
Process"
questions
Is the state of Oregon regulating
this issue?
To create an unmatched level of customer assurance, in June 2004 the
Oregon Association of Nurseries asked the Oregon Department of
Agriculture (ODA) to launch a comprehensive program to inspect and
certify nurseries and to destroy any plants found infected with
Phytophthora ramorum. The inspection and certification effort
spanned a period of 60 days and included a total of 20 U.S. Department
of Agriculture inspectors who assisted ODA staff. During the initial
inspection phase, more than 31,000 samples at Oregon nurseries were inspected and
certified free of the disease.
Oregon nurseries inspected and found free of the pathogen are being
certified. Then those nurseries enter into compliance agreements with
the ODA and are eligible to ship P. ramorum susceptible plants.
Compliance agreements require nurseries to be inspected and tested
annually, to alert ODA whenever it brings in woody plant material from
out of state, and to hold any plants on USDA’s host or associated host
list for inspection and testing if such material is received from
another noncertified nursery. Oregon certified nurseries with compliance
agreements use ODA-approved stickers to place on paperwork of shipments
of regulated plants to alert customers and regulators that these plants
originate from a certified nursery with a compliance agreement.
The Oregon Department of Agriculture has also
issued a quarantine to prevent further spread of P. ramorum within
Oregon. To view the full quarantine, click here:
http://www.oda.state.or.us/plant/ppd/path/SOD/SOD_quar.html
Back to "Regulatory
Process"
questions
Is there a
list of certified growers in Oregon?
The Oregon Department of Agriculture keeps an up-to-date list of
certified nurseries and Christmas tree growers.
Click here for a current list of certified growers.
Back to "Regulatory
Process"
questions
CONSUMER QUESTIONS
Should I be worried that plants
I am buying are
infected with P. ramorum?
Don’t worry! You can be confident that Oregon nurseries and garden
centers are serious about selling only healthy and well-cared-for
plants.
Back to "Consumer"
questions
If it can spread, what’s being done about it?
The Oregon nursery industry is taking aggressive action to make sure
that P. ramorum doesn’t become a problem here. A new state inspection
program is certifying that Oregon nurseries are free of the disease, so
only healthy, high-quality plants are sold. Plant material from
uncertified sources will be segregated, held and tested to ensure plants
do not carry the disease. If a plant is found to have P. ramorum, it and
adjacent plants are quickly destroyed. These steps will keep Oregon
plants healthy and safe from P. ramorum.
Back to "Consumer"
questions
How do I know if my plants are infected?
Ask yourself these questions:
1. Have you brought any plants in from other states or countries?
2. Have you ordered plants from a catalog or company in another state?
3. If yes, do any of these plants or the plants around them have unusual brown leaf spots or tip dieback?
Plants known to be susceptible to the
P. ramorum fungus primarily
include woody ornamentals such as camellias, rhododendrons, viburnums,
pieris and evergreen huckleberry. Most plants are not impacted by the
disease and it does not harm animals or humans. If you are concerned
about a plant’s health, take a leaf sample to your local garden center
for evaluation.
Below are some examples of infected plants
(photos courtesy of the Oregon Department of Agriculture):
Infected Camellia showing leaf browning
Infected Rhododendron leaf showing diffuse
and collapse
browning around mid-vein
Additional pictures and descriptions of the fungus and its hosts
also can be seen at the Diagnostic Guide link at:
www.suddenoakdeath.org.
Back to "Consumer"
questions
How can I help prevent the spread of P.
ramorum?
Oregon's oaks, tanoaks, huckleberries, rhododendrons and other plant
species can best be protected by preventing further introductions of the
disease to Oregon. By following these tips, you can help prevent the
spread of P. ramorum:
Do not transport oak firewood or other potentially infected plant
materials from diseased areas in California to Oregon.
Do not import potentially infected plant materials from Europe.
Do not mail order plant materials from unreliable sources.
If you visit diseased areas, wash your vehicle and shoes before
traveling to disease-free areas. This includes mountain bikes ridden in
areas with the disease.
If you think you see a host plant with suspicious disease symptoms, report it to
the
Oregon Dept. of Agriculture or the
Oregon Dept. of Forestry immediately.
Back to "Consumer"
questions
Copyright 2004