.

Date: December 21, 2007
Source: FreshPlaza [edited]
<http://www.freshplaza.com/news_detail.asp?id=13600>

USDA searches for pest in potatoes from Canada

[The US Department of] Agriculture (USDA) is tracing seed-potato shipments to Washington, Oregon, Idaho and 5 other states from Canada that it fears might have been carrying a microscopic, wormlike pest that attacks potato plants. The department has banned additional shipments into the United States and plans to search for the golden potato cyst nematode in fields in Washington, Idaho, Oregon, California, North Dakota, Colorado, Maine and Nebraska, said Larry Hawkins, a spokesman for the USDA in Sacramento, CA.

U.S. officials are concerned that discovery of the golden nematode in any of the 8 states could lead to some countries banning U.S.
potatoes, which happened in 2006 with the discovery of the similar pale potato cyst nematode in Idaho, Hawkins said Tuesday [18 Dec 2007]. The department closed the U.S. border to seed potatoes from the Canadian province of Alberta on 1 Nov 2007 after officials with the Canadian Food Inspection Agency [CFIA] on 23 Oct 2007 announced the discovery of the golden nematode at 2 farms about 60 miles [96 km] apart.

"At this point the concern we have is whether or not Canada has been able to determine what the extent of the infestation is in Canada," Hawkins said. Earlier this month [December 2007], Mexico also cut off shipments of Alberta seed potatoes. Canadian seed growers have since mounted a campaign to reopen the U.S. border.

"From our perspective we don't think [the ban] is justified," said Alain Boucher, national manager of the potato cyst nematode emergency section of the Canadian Food Inspection Agency. "Some farms have no association at all with the 2 fields, but by default they are all treated the same."

He said it is unclear how the nematode got into Alberta. Seed Potato Growers of Alberta [PGA] recently sent a letter to U.S. clients asking them to contact agriculture officials to request the restrictions be lifted. "They're lobbying very hard to get the U.S.
potato growers to accept seed potatoes, and we feel that's very risky," Hawkins said. The nematodes feed at the roots of potato plants and can reduce crop production by 80 percent. Officials say the pest is not harmful to humans and doesn't have any effect on the potatoes themselves. Seed potatoes are an inch [2.5 cm] or 2 in diameter and are often grown in colder areas at higher elevations.
When planted, they grow into potato plants that produce more potatoes.

--
Communicated by:
ProMED-mail
<promed@promedmail.org>

[Both golden (_Globodera rostochiensis_) and pale (_G. pallida_) cyst nematodes cause serious crop losses in potato. They can also infect other solanaceous crops and weeds. Symptoms on potato are stunting, yellowing, and wilting of leaves as well as a reduced root system, which is abnormally branched and brownish in colour. Damage to the crop varies from small patches of poor growing plants to complete crop failure. Diseased plants 1st occur in isolated patches and these become larger with each new crop if potatoes are continually grown on the infested site. In light infestations, potato plants may show no above ground symptoms, but yield can be reduced. Light infestations can reduce tuber size, whereas heavy infestations reduce both number and size of tubers.

The nematodes are not greatly influenced by soil type and temperature and thrive wherever potatoes are grown. The pathogens survive in soil in the absence of a host as cysts containing viable eggs. These can survive in soil, which has not been planted to potatoes, for up to 20 years. Spread occurs via infected soil, water, wind, or on plant material. It takes about 6-7 years from introduction into a potato paddock before numbers of the nematodes reach a detectable level.
Disease management includes exclusion, quarantine, and crop rotation with non-host species.

_G. rostochiensis_ is widely distributed in Europe, Africa, and Asia, and occurs in parts of the Americas. It has been included on the alert list of the European Plant Protection Organisation (EPPO). Its 1st report in Canada was in 1965 in British Columbia. Strict sanitation measures are being applied to try to prevent further spread in Canada.

Maps
Canada:
<http://www.lib.utexas.edu/maps/americas/canada_pol_1986.gif>  and
<http://healthmap.org/promed?v=55.4,-101.9,4>
Alberta:
<http://atlas.nrcan.gc.ca/site/english/maps/reference/provincesterritories/alberta/referencemap_image_view>
US:
<http://www.census.gov/geo/www/us_regdiv.pdf> and
<http://healthmap.org/promed?v=40,-97.6,4>
Worldwide distribution of golden nematode (6 Sep 2007):
<http://www.eppo.org/QUARANTINE/nematodes/Globodera_rostochiensis/HETDRO_map.htm>

Pictures
Symptoms of golden nematode on potato plants:
<http://www.dpi.vic.gov.au/CA25677D007DC87D/LUbyDesc/Ag0572a/$File/Ag0572a.jpg> 
and
<http://www.nysaes.cornell.edu/ent/bcconf/talks/images/brodie2.gif>
Golden and pale cyst nematodes:
<http://www.eppo.org/QUARANTINE/nematodes/Globodera_pallida/HETDSP_images.htm>

Links
Additional news stories:
<http://www.freshplaza.com/news_detail.asp?id=13365>  and
<http://www.freshplaza.com/news_detail.asp?id=13069>
Information on golden nematode:
<http://www.dpi.vic.gov.au/dpi/nreninf.nsf/childdocs/-71E8091F577D52D24A2568B30004F3B2-07E8C65C31CFC12CCA256BC800029303-4C9C6833948D4DF54A256DEA00274836-386AFCFE1CD9F10ECA256BCF000BBFE4?open>
Data sheet on both potato nematodes:
<http://www.eppo.org/QUARANTINE/nematodes/Globodera_pallida/HETDSP_ds.pdf>  and
<http://www.inspection.gc.ca/english/sci/surv/data/glorose.shtml>
Diagnostic techniques for both potato nematodes:
<http://www.eppo.org/QUARANTINE/nematodes/Globodera_pallida/pm7-40(1)%20HETDSP%20web.pdf>
Golden nematode in Canada:
<http://www.agf.gov.bc.ca/cropprot/goldennema.htm>
EPPO alert list:
<http://www.eppo.org/QUARANTINE/listA2.htm>
CFIA:
<http://www.inspection.gc.ca/english/toce.shtml>
PGA:
<http://www.albertapotatoes.ca/>.  - Mod.DHA]

[see also in the archive:
Golden cyst nematode, potato - Canada: (AB) 20071121.3759
Pale cyst nematode, potato - US (ID): quarantine update 20070418.1282
2006
---
Golden nematode, potato - Canada (QC)(02): USA response 20060821.2356
Golden nematode, potato - Canada (QC): 1st Report 20060816.2295]

The news item on this page is copyright by the organization where it originated - Fair use notice

Other news from this source