CFIA Website (March 30, 2005)
Regulatory proposals that were recently pre-published in the Canada Gazette, Part I - Visit CFIA site at:
Plum Pox Virus Compensation Regulations, 2004 (posted March 30, 2005)

AgNet 1 June 2004

Plum pox compensation

AGENCY: Animal and Plant Health Inspection Service, USDA.

ACTION: Final rule.

SUMMARY: We are amending the plum pox compensation regulations to provide additional compensation to affected growers, 
under certain conditions. We are providing additional compensation to growers who have already been paid compensation for 3 
years of lost production, but who are prohibited from replanting regulated articles for a total of more than 3 years due to 
additional detections of plum pox in areas already under quarantine. Such growers will be paid compensation for up to 2 
additional years. We are also providing additional compensation to growers who are direct marketers of their fruit and growers 
who have had trees that were less than 1 year old destroyed. We are taking these actions in response to issues that have 
surfaced during our 2 years of experience in managing the plum pox quarantine and paying compensation to affected growers. 
These changes are necessary to provide adequate compensation to persons affected by the plum pox quarantine and 
eradication efforts associated with the quarantine. DATES: Effective Date: July 1, 2004.

FOR FURTHER INFORMATION CONTACT: Mr. Stephen Poe, Operations Officer, Program Support Staff, PPQ, APHIS, 4700 River Road Unit 134, Riverdale, MD 20737-1236; (301) 734-8247.

VINELAND - Efforts to wipe out plum pox virus in Niagara and elsewhere in Canada were given an $85 million shot in the arm Monday.
The federal funding, to be paid out over seven years, was cheered by several in the area's tender-fruit industry.

They say the funding - announced at the federal Vineland Research Station – is needed to combat the problem and compensate growers who'll have to uproot diseased trees.

"We sure do appreciate this $85 million commitment from the federal government," said grower Kevin Buis, who's Niagara-on-the-Lake tender-fruit crop has been hit by plum pox virus.

About 16 hectares of his farm's peach trees have had to be removed, representing perhaps half of that crop.

"It's good to see the support not only for the fruit industry, but agriculture in general," said Buis. "That kind of money should have a positive impact on fruit growers."

Plum pox is not a threat to human or animal health, but the insect-borne plant disease affects tender fruit such as peaches, plums, nectarines and apricots.

In Canada, the disease was first detected in Niagara, and other areas of Ontario and Nova Scotia in 2000. It infects trees and can drastically reduce marketability and crop yields. 

Many local growers were affected and local fruit supplies to canning operations were especially hard hit. 

After 2000, tens of thousands worth of peach trees were destroyed in a $40-million effort to fight the virus.

An export ban was also placed on the region to prevent infected trees from being shipped to other areas of the country. 

A plum pox eradication program was set up in 2001 by the province and tender fruit industry and it proved successful in suppressing the disease in Niagara.

Federal and Provincial Governments To Assist Tender Fruit Industry (links to CFIA ebsite)

Encouraging Progress on the War against Plum Pox Virus (links to OMAF website)

AgNet, 20 January 2003

CFIA PLUM POX VIRUS UPDATE

AgNet, 12 August 2002 

CFIA PLUM POX VIRUS SURVEY UPDATE ­ JULY 5, 2002

Survey Status As Of July 5, 2002 (this chart can be viewed at the url: http://www.inspection.gc.ca/english/plaveg/hort/survey9e.shtml) 

Notes:

• 1. Includes sampling done by both the Canadian Food Inspection Agency and Agricorp, an Ontario Crown Corporation that is collecting samples from the Niagara Quarantine Area and other isolated quarantine areas. 
  2. These are final survey figures.
  3. Only positive blocks and samples officially confirmed by the Canadian Food Inspection Agency are listed. 

1. Survey Activities in Ontario 

The 2002 plum pox virus survey was started in mid-May in Ontario. As of July 5, 7 PPV detected blocks have been officially confirmed by the CFIA in Ontario. These PPV detected blocks have been detected within existing quarantine areas.

An international PPV panel was convened by the CFIA to review the Canadian PPV detection survey activities and suppression actions in the Niagara quarantine area. The Panel submitted a report proposing the use of more intensive sampling for more precise virus detection and modified eradication methods focussing on  reducing geographical distribution. The CFIA has adopted the Panel recommendations which are attainable during the remainder of the 2002 survey season. Other Panel recommendations will be reviewed for possible implementation in the 2003 survey season. 

The Niagara quarantine area is being partitioned into three sub-areas for survey purposes based on known virus incidence. Sub-area A is west of St. Catharines. Sub-area B is east of St. Catharines and south of highway 55. Sub-area C is east of St. Catharines and north of highway 55. Trees in positive blocks in sub-areas A and B are being individually sampled and tested. PPV detected blocks in sub-area C with higher numbers of detected trees previously removed will also be tested as individual trees. 

a. General Detection Survey Activities Outside the Quarantine Areas

The general detection survey outside the quarantine areas began on May 13. Plum pox virus has not been detected in any official test results. 

b. Niagara Quarantine Area

Sampling in the Niagara area began on May 13. The survey of plum pox virus susceptible commercial orchard blocks, homeowner properties, wild weeds, and public lands surveys are ongoing. The sampling of budwood mother trees for use within the quarantine area has been completed. 

The CFIA is collecting samples for confirmatory testing. Three (3) PPV detected blocks have been officially confirmed by the CFIA in the Niagara area.

c.  Isolated Quarantine Areas in Ontario Sampling of all plum pox virus

Susceptible commercial orchards in the Fonthill, Stoney Creek and Vittoria quarantine areas has been completed. The CFIA is currently sampling commercial orchards in the Blenheim area and finishing the homeowner survey in the Vittoria area. Four PPV detected blocks have been officially confirmed within each of the Fonthill and Blenheim zones. 

2.  Survey Activities in Nova Scotia
Plum pox virus was detected in one block in 2000. This block was removed and the virus was not detected in any other blocks surveyed in 2001. 

2a. Activities in Nova Scotia Quarantine Area

Surveying began in the Annapolis quarantine area on June 4, 2002. Sampling was started near the original positive block and expanded outwards. In total, 431 samples were collected from 11 blocks belonging to 2 growers. Plum pox virus has not been detected in any official test results. 

2b. General Survey Activities - Nova Scotia

The general detection survey began on June 7, 2002. To date 1012 samples have been collected from 166 blocks belonging to 69 growers. Plum pox virus has not been detected in any official test results. Sampling is expected to be completed the week of July 15, 2002. 

3.   Survey Activities in British Columbia

The general detection survey began on May 21, 2002. The survey was completed on June 25, 2002. The 6,359 samples were collected from 368 blocks from 121 growers and 4 nurseries. Plum pox virus was not detected in any official test results. 

4. Survey Activities in Quebec

The general detection survey began on June 17. To date 103 samples have been collected and PPV has not been detected in any official test results. 

CFIA WEBSITE UPDATE - AUGUST 2002

CFIA Plum Pox Virus Survey Update - August 6, 2002 - http://www.inspection.gc.ca/english/plaveg/hort/survey10e.shtml

CFIA WEBSITE UPDATE - JULY 2002

CFIA Plum Pox Virus Survey Update - July 5, 2002 - http://www.inspection.gc.ca/english/plaveg/protect/facren/ppve.shtml

Nouvelles sur le dépistage du virus de la sharka - Mise à jour du 5 juillet 2002 - http://www.inspection.gc.ca/francais/plaveg/protect/facren/ppvf.shtml

AgNet, 5 June 2002 

PLUM POX VIRUS

BENDERSVILLE, Pa. -- Mark Mickley and Ann Echard are, according to this story, part of the front line in Pennsylvania's fight against plum pox virus, a disease that has devastated the state's stone-fruit industry in just a few years. 

Echard, field supervisor for the state's annual plum pox survey, was quoted as saying, "The only way to know for sure if a tree is infected is to test the leaves."

The story says those tests, which will continue throughout the summer and fall in every orchard in Pennsylvania, will have a profound effect on the state's stone-fruit industry for years. 

Although common in Europe, the first North American outbreak of plum pox virus was found in an orchard near York Springs in the summer of 1999. Scientists still don't know where that strain came from. What they do know, the story says, is that it could devastate the American stone-fruit industry -- peaches, nectarines, plums and apricots. Some strains of the virus also affect cherries, although cherries seem immune to the strain in Pennsylvania. 

Plum pox is spread by aphids. An aphid feeding on a diseased leaf will take in some of the virus. If that aphid then feeds on a healthy tree, it will transmit the virus. The virus is not harmful to humans and does not kill the trees. But diseased fruit shows ugly spotting that makes it virtually unmarketable, and within a few seasons production begins to fall on diseased trees. 

European growers have tried to contain the disease, removing individual trees when an infection is found. But here, officials have taken a more aggressive approach. 

The story explains that when an infection is confirmed, every stone-fruit tree within 500 yards must be destroyed. A second perimeter is established creating a quarantine 1,000 yards around the infection. Growers are prohibited from taking trees out of or planting new trees in the quarantine area.

Penn State University plum pox site: http://sharka.cas.psu.edu/

FARMERS WILL GET THE FACTS TO FIGHT PLUM POX VIRUS: AGRICULTURE SPECIALISTS EXPECT MORE TREES WILL BE REMOVED THIS YEAR; GROWERS WILL LEARN HOW TO SPOT DISEASE

Niagara, Ontario, farmers are, according to this story, preparing for a fresh battle with the plum pox virus next growing season with the help of the Ontario government. The Ontario Ministry of Agriculture is holding information sessions Tuesday and Wednesday to assist fruit farmers in combating the virus, which is also called Sharka. The farmers will learn how to identify the presence of the virus on their fruit trees and understand how it is transmitted.  

The plum pox virus affects tender fruits such as peaches. Although it is not a risk to human health and does not kill the tree, it does make the fruit unmarketable. It is thought to have been introduced to Niagara through imported plants and spread from tree to tree by aphids. Over the past two years, thousands of peach trees have been destroyed in a bid to halt the spread of the virus. Moreover, a quarantine zone around Niagara was established by the federal government, preventing exports. 

CFIA Website Update.

Plum Pox Virus (PPV) - Update/Le potyvirus de la sharka du prunier - Mise a jour

CFIA Plum Pox Virus Survey Update - October 31, 2001:
http://www.inspection.gc.ca/english/plaveg/protect/facren/ppve.shtml

Nouvelles sur le dépistage du virus de la sharka * Mise à jour du 31 octobre 2001:
http://www.inspection.gc.ca/francais/plaveg/protect/facren/ppvf.shtml

********
DISCLAIMER/AVERTISSEMENT:
The use, distribution or publication of any material does not constitute or imply an endorsement by Agriculture and Agri-Food Canada of such material, or of any opinions or comments in such materials. 

L'utilisation, la distribution ou la publication de tout document par Agriculture et Agroalimentaire Canada n'engage pas sa responsabilité ni ne sous-tend que le Ministère souscrit aux opinions et commentaires émis.

AgNet, 29 November 2001

PLUM POX DISEASE, PLUM, NO SEED TRANSMISSION - ITALY

Further molecular evidence of the non-transmission of plum pox potyvirus through  seeds.

Plum pox potyvirus (PPV - EPPO A2 quarantine pest) is naturally transmitted in orchards by several aphid species, and is also spread by... infected propagating material. The possibility of seed transmission [is still debated]. In the past, there  have been some records of seed transmission in apricot from Hungary, and in plum  and peach from Romania [but these results could not be confirmed]. 

Further studies using serological tests [showed that] ... [PPV was present in seed coats] and cotyledons (including embryonic tissues) in seeds ... from infected apricot, plum, and peach trees, but never in seedlings obtained from infected  seeds.

The question of seed transmission of PPV was [re]addressed using serological and molecular techniques. In all, 12 different apricot and 6 peach cultivars naturally infected by PPV strains D and M, respectively, were used. All plants tested positive in immunocapture-reverse transcriptase polymerase chain reaction  (RT-PCR), and the strains (PPV-D and PPV-M) were characterized by several  molecular and serological assays. The presence of PPV was studied in ripe seeds  collected from these naturally infected plants, in germinating seeds, and in  seedlings. Seedlings were maintained in aphid-proof conditions for over 3 years  (apricot) or over 6 months (peach) and regularly tested. 

ELISA and immunocapture-RT-PCR showed that [a high percentage of ripe seeds were infected with either strain] and that the virus was mainly present in [the] seed coat, although cotyledons were also infected. Analysis during germination showed that the virus remained confined to reserve tissues and did not replicate in the meristem. 

Apricot and peach seedlings never showed symptoms and, when tested by molecular assays, always gave negative results. The authors concluded that PPV-D and PPV-M are not transmitted by apricot and peach seeds. 

Source: Pasquini G, Simeone AM, Conte L, Barba M. RT-PCR evidence of the non-transmission through seed of plum pox virus strains D and M. Journal of Plant Pathology 2000; 82(3): 221-6. 

[By using the more sensitive immunocapture-RT-PCR technique coupled with serological assays, the authors confirmed that neither strain of PPV was transmitted by seed. These results are of significance to the tree fruit nursery trade because seeds, which may or may not be virus-infected, are often used to generate seedlings to be used as root stocks, upon which desired scions will be  grafted for fruit production. ] 

AgNet, 16 October 2001 

REGULATIONS AMENDING THE PLUM POX VIRUS COMPENSATION REGULATIONS 

Information Documents: Regulatory Impact Analysis Statement Approved Amendment.

The complete document is available for download from: http://www.inspection.gc.ca/english/reg/approe.shtml

CFIA Update; 11 October 2001 (via email)

CFIA Plum Pox Virus Survey Update - September 12, 2001:
 http://www.inspection.gc.ca/english/plaveg/protect/facren/ppve.shtml 

Nouvelles sur le dépistage du virus de la sharka - Mise à jour du 12 septembre 2001:
 http://www.inspection.gc.ca/francais/plaveg/protect/facren/ppvf.shtml 

AgNet 18 September 2001

RESEARCHERS BATTLE PLUM POX IN PENNSYLVANIA

Near historic Gettysburg, Pa., federal and state scientists are facing down a different kind of threat than that once posed by General Robert E. Lee's Confederate troops: an exotic stonefruit disease called plum pox that's invaded orchards in Pennsylvania's Adams, Cumberland and York counties. 

When and how it arrived there--possibly from Europe--remains speculative. Fortunately, even before its U.S. presence was announced in October 1999, U.S. Department of Agriculture scientists had already begun researching the disease in anticipation of its arrival. Soon after the announcement, they teamed with scientists from the Pennsylvania Department of Agriculture and Pennsylvania State University to better tackle this new threat to the nation's $1.8 billion stonefruit industry. 

Through research on six basic fronts, including identification of aphid carriers and herbaceous weed reservoirs, they're helping to eradicate plum pox from the affected counties and devise strategies by which U.S. orchard managers can cope with the disease should it recur elsewhere, according to Vernon Damsteegt, a plant pathologist with USDA's Agricultural Research Service. 

Plum pox poses no danger to consumers. But it can ruin the marketability of plums, peaches, apricots and other stonefruits by causing acidity and deformities. Adams, Cumberland, and York counties in Pennsylvania are the only U.S. locations where  plum pox (strain D) has been reported. 

Since spring 2000, Pennsylvania researchers have been surveying orchards in the affected and neighboring counties to determine which aphid species occur there. At ARS' Foreign Disease-Weed Science Research Unit in Fort Detrick, Md. ( www.armymedicine.army.mil/usda ), Damsteegt and PSU scientist Frederick Gildow test the aphids to determine which actually transmit plum pox to plants. One confirmed accomplice is the green peach aphid. 

Meanwhile, ARS horticulturist Ralph Scorza in Kearneysville, W.Va., is checking the susceptibility of native and ornamental Prunus species. Both studies will help scientists find, and break, weak links in the plum pox disease cycle, as well as  monitor any possible spread to woodland areas or gardens. 

A longer story in in the September issue of Agricultural Research magazine
appears on the web at: http://www.ars.usda.gov/is/AR/archive/sep01/pox0901.htm

AgNet 18 September 2001

A POX ON THAT VIRUS! ATTEMPTS TO ERADICATE PLUM POX VIRUS

http://www.ars.usda.gov/is/AR/archive/sep01/pox0901.htm

Plum pox potyvirus (PPV) is a devastating disease of wild and cultivated Prunus species, which include plums, peaches, apricots, nectarines, and many other stone fruits. The disease manifests as yellow rings and blotches on leaves or fruit. Although not a danger to consumers, PPV can ruin the fruit's marketability by increasing acidity and causing deformities.

In Europe, 100 million trees are infected, and PPV has made a small but worrisome foray into the United States, limited so far to several orchards in and around Adams County, Pennsylvania. 

But plant scientists haven't been completely caught off guard. Since 1991, four USDA scientists‹Vernon Damsteegt, Laurene Levy, Ann Callahan, and Ralph Scorza‹have conducted basic research in anticipation of just such an invasion, including development of a transgenic plum tree that resists the virus (see story on page 11). 

When and how PPV entered the United States remains speculative. But shortly after its presence was announced in October 1999, the team's work took on new urgency, says Damsteegt, a plant pathologist with ARS' Foreign Disease-Weed Science Laboratory at Fort Detrick, Maryland, about a 45-minute drive from the infected Pennsylvania orchards. Cooperative ties were soon forged with research teams at Pennsylvania State University (PSU), the Pennsylvania Department of Agriculture (PDA), and groups in Europe. 

Levy, one of the first to confirm the disease, is a plant virologist with USDA's chief regulatory arm, the Animal and Plant Health Inspection Service (APHIS), in Beltsville, Maryland. Scorza, a horticulturist, and Callahan, a geneticist, are both assigned to another ARS lab. When PPV emerged in Pennsylvania, APHIS  quarantined all stone fruit trees, seed, budwood, and nursery stock in a  4-square-mile Adams County area to keep PPV from escaping via plant material bound for other U.S. stone fruit regions. 

Over 1,000 acres of stone fruit trees have been destroyed so far, with grower indemnities totaling $12 million, reports Stephen Poe, an APHIS domestic and  emergency operations officer. 

Plotting Against Plum Pox

The PPV research focuses on six fronts: epidemiology, herbaceous weed host identification, wild and ornamental Prunus species susceptibility, insect transmission, molecular detection and characterization, and disease resistance in cultivated Prunus crops. Eradicating PPV from the Adams County area is the ultimate goal, "one that we should be able to achieve in the next few years," says Poe. Even then, scientists aren't taking any chances. They're building a body of knowledge that U.S. stone fruit growers can draw on to cope with the disease if it recurs. 

"If we could eradicate the pathogen, it would be a historic achievement," says Frederick Gildow, a professor at PSU's Plant Pathology Department who assists with the collection, rearing, and study of insects known to spread PPV. But "it's likely  that there could be future invasions of this virus. By doing the research now, we'll  all be better prepared for the next time around."

Culprit and Accomplice

Their target is strain D, one of four PPV serogroups (D, M, C, and EA) that plague stone fruits and other Prunus species in Europe, the Mediterranean, Balkan States, Middle East, India, Chile, Canada, and elsewhere. Strain D is less aggressive than the others and is the only PPV strain reported in North America, notes Levy. She and Vessyla Mavrodieva, a postdoctoral scientist from Bulgaria, have sequenced the genomes of two strain D specimens isolated from an Adams County peach and  plum tree. Andrew Stone, a biologist at ARS' Fort Detrick lab, is sequencing a third  isolate from the same area for comparison. 

PPV is transmitted by aphids, small, teardrop-shaped insects with a sharp mouthpart called a stylet for sucking out plant sap. About 20 aphid species worldwide are known to transmit PPV to Prunus plants. Since spring 2000, Pennsylvania entomologists Jim Stimmel and Greg Krawczyk have conducted extensive surveys of orchards in Adams and neighboring counties, identifying the aphid species that live there. Gildow and Damsteegt have begun studies to  examine these insects' ability to transmit Pennsylvania strain D. One Adams County accomplice they've fingered is the green peach aphid, Myzus persicae. 

Inside the ARS quarantine facility at Fort Detrick, where live strain D specimens can be safely studied, hundreds of hungry aphids are mixed with PPV-infected  leaves. After 10 to 30 minutes the aphids are placed in cages over healthy test  seedlings for 24 hours and then killed. Scientists monitor the seedlings for 30 days  for evidence of PPV infection. The researchers also use immunological assays to  confirm infection. 

A Deadly Duo

The plum pox virus itself is little more than a filament of RNA surrounded by a protein coat. Once transmitted, it uses the host plant's cells to replicate and spread. 

Aphids transmit PPV while test-probing the plant's epidermal layer, not while mining the phloem for sap. Though transmission takes just a few seconds, the degree to  which plants become infected varies by season, host crop, variety, age, aphid species, and other factors. 

PSU researcher John Halbrendt coordinates surveys of weed species that may harbor PPV and are fed on by aphids. Says Damsteegt, "We follow up on those studies by looking at 'clean' plants of those reservoir species and inoculating them with the virus to find out whether it will make them sick." 

Likewise, Scorza and research technicians Kevin Webb, Mark Demuth, and Phaedra O'Connell are inoculating native and ornamental Prunus species with strain D to  evaluate their susceptibility. "This information is important to monitoring any spread of the virus to woodland and garden trees," says Scorza.  

By compiling and analyzing such information, the team hopes to understand strain D's cycle of disease, starting with the aphids' overwintering habitat, seasonal  migration, and host plant feeding. 

"We can show in the lab that a plant can be a host, but in the field it has to be something that's frequented by aphids and plays a part in their life cycle," says Damsteegt. "The crux of the matter will be determining what aphids there are, which of these actually transmit the disease, and where they go from there." 

This understanding will help officials and commercial growers take steps to deprive PPV of its avenues of attack and escape from Adams County. But spraying  orchards with insecticide may not be the solution, since chemicals don't kill the  aphids on contact, which gives them time to transmit PPV. 

"The key is to stop them before they take flight," Damsteegt notes, "or try to disrupt their life cycle." Around orchards, for example, this could mean depriving aphids of overwintering sites or hiding places by killing host weeds. 

High-Tech Monitoring

PPV eradication efforts hinge on continual surveying of aphid and weed populations. To expedite this, Damsteegt and Stone are working to combine two common diagnostic tools: serological kits and genetic fingerprinting. The kits use  antibodies to bind to and help detect a pathogen by the specific antigens it  produces, such as a protein. The fingerprinting technology is based on revealing  amplified sequences of a pathogen's unique nucleic acid coding. The idea is to  combine the serological kit's ease of use with genetic fingerprinting's sensitivity  and reproducibility to furnish real-time results during field surveys. Our goal is to develop faster, more sensitive detection methods that can be used with large numbers of samples, says Damsteegt. In the war on plum pox, such capabilities will prove ever more important in rooting out its hiding places.

AgNet 18 September 2001

ONE GENE MAKES THE DIFFERENCE‹FOR PLUM POX RESISTANCE

http://www.ars.usda.gov/is/AR/archive/sep01/gene0901.htm

Standing in an ARS orchard are three genetically engineered plum trees, simply dubbed "C5." They look like their female parent‹Bluebyrd‹a commercial cultivar developed through traditional breeding by ARS horticulturist Ralph Scorza. And their fruit tastes the same.

The difference, says Scorza, is that C5 was given a gene that allows it to resist plum pox virus (PPV) infection. Scorza, who also developed Bluebyrd, says the gene turns off, or "silences," the production of a protein essential for PPV to infect the tree. 

"It's basically immune to the plum pox virus. We've shown that it is resistant to all major strains of the virus that we've tested," he says. Even if C5 is grafted onto  PPV-infected rootstock, virus levels remain so low that aphids apparently can't pick it up and spread it to other trees. And that's critical for maintaining the health of  U.S. stone fruit orchards. 

"You want something that's totally resistant, so that you don't harbor the virus unknowingly," Scorza explains. "Tolerant trees can harbor lots of the virus without  any visible symptoms, and then it's easily transmitted by aphids." Scorza says the fruit quality of C5 is good enough for commercial use.  What's more, the tree transfers its viral resistance to its seedlings, so breeders could use it to develop new resistant varieties. The tree first proved its resistance under strict quarantine  in ARS greenhouse studies, jointly conducted by the ARS team of Scorza, Vern Damsteegt, and Ann Callahan, and APHIS' Laurene Levy. Now, it has completed its fifth year of testing by researchers in three European countries where the virus is well established. 

ARS technology-transfer specialists can't say when the tree will be available for commercial release because it's breaking new ground. It is the first tree for temperate climates to be given a gene for virus resistance and is subject to strict regulation. Moreover, the pieces of DNA (and the genetic techniques) are all from different sources. And several are patented. 

Michel Ravelonandro at INRA, the French counterpart of ARS, provided the plum pox resistance gene. Dennis Gonsalves at Cornell University in Ithaca, New York, provided a souped-up vector (an Agrobacterium) for inserting the gene. ARS has filed a patent on C5 to encourage an industry partner to pull all these threads together toward commercialization. 

Then, U.S. stone fruit growers can breathe a sigh of relief, knowing they have a backup tree to plant. And U.S. consumers may prefer a transformed plum to no plum at all. 

"In every other way," says Scorza, "C5 acts like a normal plum tree." (By Judy McBride, Agricultural Research Service Information Staff.)

AgNet; 7 September 2001 (via AgJournal)

GENETICALLY MODIFIED TREES RESIST PLUM POX VIRUS

A genetically modifed plum tree, dubbed "C5", is basically immune to the plum pox virus. "We`ve shown that it is resistant to all major strains of the virus that we`ve tested," says Ralph Scorza, horticulturist with the U.S. Department of Agriculture`s Agricultural Research Service (ARS). But, although the fruit quality of C5 is good enough for commercial use, it`s not clear when plum pox-resistant trees will be released to growers. The C5 tree looks like an ordinary plum tree and produces fruit that looks and tastes the same. But a single gene allows the C5 tree to resist plum pox virus infection. Even if C5 is grafted onto plum pox-infected  rootstock, virus levels remain so low that aphids apparently can`t pick it up and  spread it to other trees. "You want something that`s totally resistant, so that you don`t harbor the virus unknowingly," Scorza explains. "Tolerant trees can  harbor lots of the virus without any visible symptoms, and then it`s easily transmitted by aphids." A C5 tree transfers its viral resistance to its seedlings, so breeders could use it to develop new resistant varieties. The first tree for temperate climates to be given a gene for virus resistance, C5 has completed its fifth year of testing by researchers in three European countries where the virus is well-established. However, testing to meet regulatory requirements continues. In addition, the pieces of DNA - and the techniques used to transfer them - are all from different sources. And several are patented. The ARS has filed a patent on C5 to encourage an industry partner to pull all these threads together toward commercialization. Plum pox is a viral disease of stone fruit species (such as  peaches, and plums) that first appeared in North America in October 1999. In March 2000, the U.S. Secretary of Agriculture took emergency action in order to eradicate infected trees and prevent the spread of the virus from Adams and Cumberland Counties of Pennsylvania to the rest of the United States and to other countries. The disease has also been found in Canada. For more information on  plum pox virus, see this Animal and Plant Health Inspection Service Web site. 

AgNet 22 June 2001

PLUM POX FIGHT GAINS $40-MILLION INJECTION

The federal and provincial governments are, according to this story, investing $40 million to try and eradicate the plum pox virus in Canada. But the injection is bringing more than cash to Niagara farmers. It's also bringing relief.

The story says that the announcement comes just months after word in the local industry was that the Canadian Food Inspection Agency was going to stop trying to eradicate the virus because it was too widespread.

Len Troup, chairman of the Ontario Tender Fruit Producers' Marketing Board, was cited as saying he believes the money will be enough to make a difference in wiping out the disease, adding, "I couldn't ask for more. We're thrilled that they listened to us.''

Today in Ottawa, officials with both governments will put together guidelines for assessing the worth of infected trees that were destroyed, said Larry Martin, a senior researcher with the George Morris Centre in Guelph, an agriculture think-tank. The compensation package should be known by summer's end, he said.

AgNet 2 May 2001 

PENNSYLVANIA BATTLING PLUM POX VIRUS

The plum pox virus outbreak in Pennsylvania continues to worsen, and state ag-officials are working with landowners to verify problem fields, identify susceptible trees and sampling and testing trees. 

While the virus poses no threat to consumers, the fruit from infected trees can still be eaten fresh or processed and it is an ³extremely serious threat² to the peach, nectarine, apricot and plum industry of Pennsylvania, because it drastically reduces a tree's ability to produce fruit. 

The ag department also reminds growers that there are restrictions in place on planting plum pox virus-susceptible trees or shrubs in the virus quarantine zones in Adams and Cumberland counties. Those restrictions cover all of Dickinson Township, South Middleton Township and Mount Holly Springs in Cumberland County. In Adams County, the areas affected are Huntington Township, Latimore Township, York Springs, the northern portion of Tyrone Township, and the eastern portion of Menallen Township.

The restrictions on planting strengthens the quarantine and will help the department of agriculture conduct an efficient and effective survey focused on locating infected trees. Infection of the plum pox virus in trees  can take years before detection is possible,² explained Pennsylvania Agriculture Secretary Sam Hayes.  ³The planting of more trees during this process complicates the survey, adds cost and increases to the number of times property owners must be contacted by surveyors, and poses an increased risk to our fruit growers. 

We need the help of everyone in the quarantine zone -- backyard fruit growers, homeowners, renters,  businesses and commercial growers -- to help eradicate this fruit tree disease so that the huge economic losses being experienced by the fruit industry are not in vain,'' he added. 

Since the virus' discovery in Adams County in September 1999, the Pennsylvania Department of Agriculture, in conjunction with the U.S. Department of Agriculture, has conducted extensive surveys and  more than 70,000 lab tests last year to establish a quarantine area. 

The Commonwealth has invested more than $5.1 million to eradicate the plum pox virus and indemnify farmers. 

AgNet 23 April 2001  

A POX ON YOUR PLUMS: NIAGARA'S TENDER FRUIT GROWERS, NURSERY OWNERS GRAPPLE WITH DEVASTATING TREE VIRUS

Less than a year after plum pox virus was discovered for the first time in Canada, Niagara's tender fruit growers, nursery owners and the region's fruit processing plant are still, according to this story, grappling  with the discovery. 

Len Troup, chairman of the Ontario Tender Fruit Producers' Marketing Board, was quoted as saying, "We are just at the emerging stages of the disease.'' The story says that the virus, also known as Sharka,  lead the Canadian Food Inspection Agency to order the destruction of more than 12,000 trees, or less than one per cent of the province's stone fruit trees, susceptible to the plant disease. 

Affecting stone fruit trees including peaches, plums, nectarines and apricots, plum pox virus also affects  Prunus ornamental plant varieties. While the disease does not kill trees they are destroyed to prevent the disease's spread. Spread via aphids or the grafting of infected trees, the virus causes spots and rings on  fruit. Serious strains of the virus found in Europe lead to low sugar content in fruit. 

The story also says that the province's Tender Fruit Marketing Board and Landscape Ontario, the  association representing nurseries, are keeping tight lipped about the exact financial burden caused by the  virus. They are awaiting the federal government's decision on a compensation package. It's a wait that has lasted since November. 

The story explains that Guelph's George Morris Centre was commissioned by the provincial and federal governments to research the economic impact of plum pox on the industry. The independent agri-food think tank has submitted its report, estimating losses to growers, processors and nurseries. While the estimated loss to growers hasn't been made public, a provincial Agriculture Ministry report made public by  a Hamilton newspaper put it at between $1 million to $2 million. 

AgNet 18 April 2001    

PLUM POX WILL NEVER BE ELIMINATED, GROWERS TOLD: BUT FARMERS DISAGREE; WANT VIRUS KEPT IN CHECK

Last week, during a meeting with Canadian Food Inspection Agency, Adrian Huisman, according to this story, heard the words that made the blood of every Niagara peach farmer run cold.  Plum pox virus eradication will stop. 

Huisman, secretary of the Ontario Tender Fruit Producers Marketing Board, was quoted as saying, "They told us the virus was so widespread in Niagara it could never be eliminated from the area. We disagree with them.'' The story says that the proposed end of the survey and eradication programs, designed to keep the virus under control, has farmers who are already stressed losing more sleep. 

Huisman was further cited as saying that without an eradication program, the virus could run through local  orchards unchecked, adding, "This has raised question marks for everyone here,'' and that if the proposal  becomes reality, Ottawa would ``totally abandoned this industry.'' 

Blake Ferguson of the CFIA was cited as saying that the CFIA says there is no reason to panic yet, adding, "No final decision has been made in regards to the eradication program. There are ongoing talks to deal with the issue and we are trying to come to a decision as quickly as possible.'' 

In fact, time is of the essence for Niagara fruit farmers in the midst of planting season. Many still don't know if they will plant new trees to replace those infected with the virus last summer.

AgNet 13 March 2001   

PLUM POX PAYOUTS ELUDE PEACH GROWERS: COMPENSATION NEWS AWAITED WHILE APRIL PLANTING PLANS PROCEED

According to this story, Niagara peach growers preparing to plant fruit trees next month don't yet know if they'll be compensated for the trees they had to destroy last year because of plum pox virus. Growers have been waiting months for a decision from Agriculture and Agri-Food Canada. 

Adrian Huisman, manager of the Ontario Tender Fruit Producers Marketing Board, Monday was quoted as saying, "The government acts slow. But this is ridiculous.'' The fate of about 160,000 stone-fruit trees waiting in cold storage in nurseries is also unknown, said Huisman. In four weeks, farmers will start planting in their orchards, said Huisman.  The Canadian Food Inspection Agency ordered about 12,000 trees destroyed as a result of the virus. The vast majority of trees were peach. "It is only fair that someone be compensated,'' said Blake Ferguson, of the Canadian Food Inspection Agency.

There is a restriction on the movement of these plants until a decision is made to determine if they can be planted.

AgNet January 27, 2000  

PA AGRICULTURE DEPARTMENT DECLARES MORATORIUM ON PLANTING IN PLUM POX VIRUS QUARANTINE AREA COVER PARTS OF ADAMS AND CUMBERLAND COUNTIES

HARRISBURG, Pa. -- Pennsylvania State Agriculture Secretary Samuel Hayes Jr. today declared a moratorium on the planting of Plum Pox Virus (PPV)-susceptible trees or shrubs in the Plum Pox Virus quarantine zones in Adams and Cumberland counties. The moratorium includes residential or business plantings, as well as new plantings in commercial orchards. The planting moratorium covers the same geographic area as the quarantine, including all of Dickinson Township, South Middleton Township and Mount Holly Springs in Cumberland County. In Adams County, the area affected is Huntington Township, Latimore Township, York Springs, the northern portion of Tyrone Township and the eastern portion of Menallen Township. 

"We need the help of everyone in the quarantine zone -- backyard fruit growers, homeowners, renters, businesses and commercial growers -- to help eradicate this fruit tree disease so that the huge economic losses being experienced by the fruit industry are not in vain," Secretary Hayes said.  "Plum Pox Virus is an extremely serious threat to the stone fruit industry of Pennsylvania, and it is our goal at the Department of Agriculture to help lead the fight to eradicate this virus. The planting of Plum Pox Virus-susceptible trees and shrubs anywhere in the quarantine area would make additional host material available for virus infection and jeopardize the opportunity to eradicate the virus." The moratorium on planting strengthens the quarantine by stopping all planting of potential hosts in the quarantine area and will help the Department of Agriculture conduct a more effective survey in locating infected trees. 

Detection of the Plum Pox Virus in trees can take years. The survey will need to continue for several years to make sure that trees testing negative last year are not actually harboring the virus. The addition of more trees during this process complicates the survey, adds cost and the adds to the number of times property owners must be contacted by surveyors. The moratorium will help speed the lifting of the quarantine by helping the Commonwealth to reach Plum Pox free status. Once that goal is reached, growers and homeowners can resume planting of stone fruit trees without the threat of Plum Pox Virus.

Currently, commercial growers have destroyed nearly 900 acres of infected and exposed trees to help eradicate the Plum Pox Virus. Discovered in Adams County in September 1999, the Pennsylvania Department of Agriculture conducted extensive surveys and tests to establish a quarantine area.

Plum Pox Virus causes a disease in stone fruit, such as peaches, nectarines, plums, apricots and related ornamental trees in the genus Prunus. These varieties and hybrids are hosts of the virus strain present in Pennsylvania. Other hosts include many ornamental plants such as the purple leaf plum, sand cherry, flowering almond and flowering peach. 

Aphids spread the virus from infected to healthy trees. This viral disease, known as sharka, is a limiting factor for stone fruit production in areas of the world where it occurs. Sharka does not have an effect on animals or humans.

When sharka was identified in Pennsylvania, it triggered surveys of commercial fruit tree orchards across the Commonwealth and other fruit-growing areas in the United States and Canada. Surveys  also were conducted for susceptible trees on residential properties in the area were sharka was discovered in orchards. The survey in the United States concluded that the virus is confined to a relatively small area in the northern part of Adams County and across the border in Cumberland County, establishing the Plum Pox Virus quarantine zone. The quarantine prohibits the movement of susceptible trees and propagation material, within or out of the quarantine area. 

Pennsylvania has invested more than $5.1 million to eradicate the Plum Pox  virus and indemnify farmers. 

If there are any questions about the moratorium or Plum Pox Virus, please
contact the Department of Agriculture at 717-772-5203.  

Web site: http://www.state.pa.us/

AgNet January 25, 2000  

ARS RESEARCHERS AND A COLLEAGUE IN SCOTLAND HAVE ADAPTED A STRATEGY THEY DEVELOPED FOR CITRUS TRISTEZA VIRUS TO MORE ACCURATELY SAMPLE LARGE AREAS FOR PLUM POX VIRUS (PPV)

January 23, 2001
United States Department of Agriculture

Tim R. Gottwald, U.S. Horticultural Research Laboratory, Ft. Pierce, FL  http://www.ars.usda.gov/is/qtr/q300/cdp300.htm  This method, called hierarchical sampling (HS), will be used in the U.S.Department of Agriculture's $1.4 million national PPV surveillance program. Stone fruits, such as peaches and plums, are highly susceptible to PPV. The value of U.S. stone fruit production was $1.3 billion last year. 

Previous sampling methods used for spotting diseases and their causative agents on citrus and other crops are based on the number of infested soil samples, disease lesions on a leaf, proportion of diseased fruit, or number of insects found on each plant. Unfortunately, the methods don't quantify the amount of disease present in any given tree. HS relies on the theory that it's possible to predict disease at one scale by sampling at another. By sampling only 6.25 percent of the trees in a given orchard in groups of four trees, the location of the trees in the orchard is critical, and using unique statistical methods, scientists are able to accurately predict the incidence of infection in the whole orchard. After performing thousands of simulations, researchers have shown HS to be much more accurate at detecting plum pox virus infestation than other sampling methods.

AgNet December 31, 2000  

PLUM POX TRACED TO NIAGARA NURSERY: MONTHS OF INVESTIGATION LED FEDERAL RESEARCHERS TO NIAGARA-ON-THE-LAKE

The Standard (St. Catharines - Niagara)

The Ontario source of a plum pox virus outbreak has, according to this story, been traced to a Niagara-on-the-Lake nursery. The story says that investigators from the Canadian Food Inspection Agency have reportedly located the source of the sharka plum pox virus after months of exhaustive research. 

Ontario Tender Fruit Producers Marketing Board manager Adrian Huisman was cited as confirming the outbreak's link to a Niagara nursery Friday, adding, "It happened from some of the original peaches where the virus started. Some of the bud wood from those trees was taken by an area nursery. They propagated additional trees and sold the trees across Ontario. It happened to be a couple of good varieties of clingstone peach.'' Investigators have reportedly said the nursery was supplying growers, who were in turn sending their peaches to Nabisco Ltd.'s Niagara-on-the-Lake canning plant. Huisman, however, did not name the nursery, stating, "I couldn't tell you, but it still wouldn't accomplish anything.''

An official from the CFIA was unavailable for comment Friday.

AgNet August 14, 2000  

CFIA Plum Pox Virus Survey Update

Canadian Food Inspection Agency
http://www.cfia-acia.agr.ca/english/plaveg/hort/survey2e.shtml

On June 23, 2000, the Canadian Food Inspection Agency (CFIA) confirmed the presence of Plum Pox Virus (PPV) in an orchard in the town of Niagara-on-the-Lake, Ontario. PPV was discovered in three Fantasia nectarine trees at two sites. Laboratory testing by the CFIA's Centre for Plant Health in Sidney, B.C. confirmed the virus was PPV strain-D, the same strain of PPV that was found in Prunus trees in Pennsylvania in October 1999. PPV does not affect human or animal health. 

PPV is a serious disease infecting stone fruit species of the genus Prunus including peaches, nectarines, plums, apricots, almonds and ornamental varieties. Plum Pox Virus does not kill trees, but makes fruit unmarketable and can drastically reduce yields in susceptible varieties. There is no treatment for infected trees. They must be destroyed to prevent the spread of the disease. PPV is spread over short distances by aphids and over larger distances through grafting of infected budwood or nursery stock. 

Survey Update

As of July 21, the CFIA had sampled for PPV from areas immediately around two initial positive sites in St. Catharines. In the past two weeks, CFIA sampling teams have continued to survey PPV-susceptible trees in the Niagara Peninsula, and as of August 9, had collected a total of 22,885 samples. Of these, additional positive samples have been confirmed at the three original sites. Positive samples have also been confirmed at 11 new locations: nine in the town of Niagara-on-the-Lake and two in St. Catharines. This brings the total number of positive samples to 423 (out of 17,647 tested), clustered at 14 locations. 

Sampling continues both around the positive sites and at other orchards across the Niagara Peninsula. Along with the Centre for Plant Health in Sidney, B.C., samples are also being sent for testing to the CFIA Centre for Plant Quarantine Pests in Nepean, Ontario. A third laboratory in Charlottetown, P.E.I. should be accepting samples within a few weeks.
A detection survey is currently being planned to allow for sampling across the entire production area in order to determine the overall spread of the virus in Ontario. A broader survey will also take place in other regions of Canada, including B.C. and N.S., at the onset of cooler temperatures in late  summer.


As of Wednesday, August 9, 2000 

Total PPV - susceptible Prunus Samples Collected = 22885
Total PPV - susceptible Prunus Samples Tested* = 17647
Total PPV-Positive Site Locations (11 in Niagara-on-the-Lake, 3 in St. Catharines) = 14
Total PPV - Positive Samples = 423
Total PPV - Negative Samples = 17224

*Sample testing always lags behind sample collection due to sample delivery and laboratory test processing. 

For more information on the Plum Pox Virus contact: CFIA Plum Pox Virus General Inquiries (toll-free): 1-877-854-1599 or visit the CFIA Website: www.cfia-acia.agr.ca