April 21, 2006
From: ProMED-mail<promed@promedmail.org>
Source: Seattlepi.nwsource.com and Associated Press [edited] <http://seattlepi.nwsource.com/local/6420AP_ID_Potato_Pest.html>

Japan, Mexico, Canada block fresh potato imports because of pest

Japan has banned all fresh U.S. potato imports, and Canada and Mexico all fresh potato imports from Idaho, after a microscopic wormlike pest called the potato cyst nematode was found on an eastern Idaho farm this week.

The discovery of the pest was the 1st time this particular nematode has been detected in the United States, said Pat Takasugi, director of Idaho's Department of Agriculture.

Takasugi said Friday [21 April 2006] he doesn't expect any U.S. states to ban Idaho potatoes, because his agency and the U.S. Department of Agriculture have quarantined fields and a shed at the farm where the nematodes were found.

"We have definitely caught this in the early stages," Takasugi said.

The bans by the 3 countries only involve fresh potatoes not those processed into French fries and other food products.

The pest is not harmful to humans and doesn't have any effect on the potatoes themselves, Takasugi said. But it feeds on the roots of the potato plant and can reduce crop production by as much as 80 percent.

Idaho is the nation's largest potato producer, growing about 1/3rd of all the potatoes in the United States. Last year [2005], the state produced 12.5 billion pounds of potatoes that paid farmers about USD 700 million, said Frank Muir, president of the Idaho Potato Commission. Muir estimated the industry is worth about USD 2 billion to the state.

There are several nematodes that affect potato crops; a cousin to the one found in Idaho has been found in New York and British Columbia and has prompted Canada to impose some trade restrictions on New York potatoes, said Alain Boucher, a seed potato specialist with the Canadian Food Inspection Agency. The nematode found in Idaho also has been detected in the eastern Canadian province of Newfoundland, Takasugi said.

"It's a major pest in a potato state," said Takasugi, adding that 500 acres of fields at the farm where the nematode was found have been quarantined as well as the shed used for potato storage. "That's why we've taken the most extreme measures to confine and isolate."

Potato industry experts hastened to assure consumers that the pest is not harmful to humans and that the 2 nematodes found were discovered after years of intensive testing.

The state Agriculture Department has been testing soil samples for more than 20 years, Takasugi said. The department has taken more than 10 000 samples in the last 3 years alone, "on soil, in farms, and on processing plants, and every one has been negative for the potato cyst nematode until this one find," Muir said. "Our researchers literally found the needle in the haystack."

Farmers, too, do their own tests for this nematode, said Keith Esplin, a former potato grower who is executive director of the Potato Growers of Idaho in Blackfoot.

"All indications are that it's a very minor infestation," Esplin said. "We want to be careful we don't spread it around or introduce it, but it doesn't appear that that's happened. I think we caught it in time."

It was not immediately clear how much the Canadian, Mexican, and Japanese markets are worth to Idaho. The annual value of all fresh potato exports from the United States is USD 100 million, said Melissa O'Dell, a spokeswoman for the U.S. Department of Agriculture's Animal and Plant Health Inspection Service.

Canada is Idaho's largest export market for fresh potatoes, Muir said. Idaho produces 1/3rd of the U.S. potatoes shipped to Mexico.

Idaho has invited Japan, Mexico and Canada to send health inspectors to observe how Idaho was handling the infestation, and Takasugi and Muir said they were confident all 3 countries would soon reopen trading.

"After they see the data, the tests, and everything we've done, the recommendation will probably be to lift that ban," Takasugi said.

[Byline: Anne Wallace Allan, Associate Press Writer]

--
ProMED-mail
<promed@promedmail.org>

[The crop plant potato (_Solanum tuberosum_) is susceptible to the potato cyst nematode (PCN). It is found in many places where potatoes are grown, including Europe. There are 2 species of PCN affecting crops. The white or pale PCN (_Globodera pallida_) is now believed to be the more dominant species in Europe, while the yellow or golden PCN (_G. rostochiensis_) still causes serious losses in some areas.
Prior to this report [21 Apr 2006], _G. pallida_ was only known in Newfoundland, Canada in N. America (see link for worldwide distribution map). _G. rostochiensis_ is known in New York state in mainland USA and on Vancouver Island, British Columbia and Newfoundland in Canada. Because of an effective US State and Federal quarantine which has been in existence for over 50 years, PCN/GN remains confined to portions of 9 counties within the state of New York. These 2 pathogens were described in some detail in a recent post [20060413.1092], which should be consulted along with this post.

Potato cyst nematodes are major pests of the potato crop in cool-temperate areas. This situation is, at present, more serious in the case of _G. pallida_ because of the lack of commercially available potato cultivars having resistance to this species. The amount of damage, particularly in relation to the weight of tubers produced, is closely related to the number of nematode eggs per unit of soil. It has been estimated that approximately 2 t/ha of potatoes are lost for every 20 eggs/g soil. Up to 80 percent of the crop can be lost when nematode populations are raised to very high levels by repeated cultivation of potatoes.

This 1st report of white/pale PCN (_Globodera pallida_) in the USA on a single farm in eastern Idaho is clearly very significant nationally as well as to Idaho. The farm has been placed under quarantine regulations. Despite the very restricted location, the discovery has already resulted in quarantines being places on potatoes. Japan has banned all fresh U.S. potato imports, and Canada and Mexico all fresh potato imports from Idaho. It is to be hoped that the confidence expressed by the State of Idaho's Department of Agriculture that this isolated outbreak can be contained is a correct assessment. The past exhaustive and up till now negative testing in Idaho that is described in the article should be grounds for confidence, but I anticipate more news on this topic in the immediate future. It is worth noting the following quote taken from the 1st of the "Links:"
"Because of yield loss and adverse regulatory impact caused by this nematode, the risk posed by this pest to the United States is very high."

Map:
Idaho, USA
<http://www.merriam-webster.com/cgi-bin/nytmaps.pl?idaho>

Worldwide distribution of pale cyst nematode <http://www.eppo.org/QUARANTINE/nematodes/Globodera_pallida/HETDPA_map.htm>

Pictures:
Pale/white(PCN/pale) and yellow/golden (PCN/golden)cysts on potato roots <http://www.eppo.org/QUARANTINE/nematodes/Globodera_pallida/HETDSP_images.htm>
Field symptoms
<http://magallanes.sag.gob.cl/cultinem.jpg>

Links:
<http://nematode.unl.edu/pest5.htm>
<http://www.eppo.org/QUARANTINE/nematodes/Globodera_pallida/HETDSP_ds.pdf>
<http://plpnemweb.ucdavis.edu/nemaplex/taxadata/G053S1.HTM>
<http://www.inspection.gc.ca/english/sci/surv/data/glorose.shtml>
- Mod.JAD]


[see also in the archive:
Cyst nematodes, potato, soybean - USA (NY, IL): new strains 20060413.1092
2005
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Potato cyst nematodes - Russia (Kurgan) 20050809.2322 Potato cyst nematodes, Russia (Altai Region) 20050707.1921
2004
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Potato cyst nematodes, survey - UK (England, Wales) 20040106.0056 Potato cyst nematode - Indonesia (Malang) 20040821.2326 Potato cyst nematodes - Croatia 20040830.2420
2002
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Potato nematodes, potato - Czech Republic 20020106.3168 Potato cyst nematode, potato - Hungary 20021012.5538 Potato cyst nematode, potato - Czech Republic 20021228.6141]