.

November 20, 2007
Source: Alberta Farmer Express (AFE) [edited]
<http://www.albertafarmexpress.ca/issues/ISArticle.asp?id=76601&PC=FBC&issue=11202007>

The United States border has been closed to seed potatoes from Alberta after the plant pest golden nematode was found on 2 seed potato fields.
Staff with the Canadian Food Inspection Agency [CFIA] and Potato Growers of Alberta [PGA] confirmed that CFIA and the US Department of Agriculture [USDA] have agreed to close the border to prevent the pest's potential spread. USDA and CFIA were in talks as of Tuesday [20 Nov 2007] to determine when the border would open again.

Golden nematode and pale cyst nematode are both considered quarantine pests because they can reduce yields of host crops, such as potatoes and eggplants, by up to 80 per cent and can survive dormant in host soil for decades. Both species of potato cyst nematode (PCN) have been found in 65 countries worldwide, including the US. Both have also been confirmed in Newfoundland, while golden nematode is also found in Quebec and on Vancouver Island. Alain Boucher, national manager of CFIA's potato cyst nematode emergency section, said that the border closure is a "cautionary measure" while soil samples are taken to see what populations of the pest, if any, can be found in the 2 fields in question.

PGA noted in a statement on its website that out of 284 and 143 samples taken on the 2 fields in question, respectively, only one each turned up positive. Another round of tests with 610 samples in total from both fields turned up negative for PCN. The province wide PCN survey, meanwhile, turned up only the 2 positive samples out of 2721 in total from across the province. Another 801 soil samples from the 2006 seed potato crop were also PCN-negative, the growers' association reported.

Many US potato growers in Washington, Oregon, and Idaho are known to rely on Alberta seed potatoes. "It is essential that trade resume within several weeks to meet early season commitments," PGA said in its statement.

--
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 first 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 states:
<http://www.census.gov/geo/www/us_regdiv.pdf> and <http://healthmap.org/promed?v=40,-97.6,4>
Worldwide distribution of golden nematode (September 06):
<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
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:
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