A ProMED-mail post
<http://www.promedmail.org>
ProMED-mail is a program of the
International Society for Infectious Diseases <http://www.isid.org>
Date: Wed 4 Dec 2013
Source: Capital Press [edited]
<http://www.capitalpress.com/article/20131204/ARTICLE/131209956/1318>
Ring rot testing in seed tubers
-------------------------------
Potato industry officials anticipate much greater interest in winter testing of seed [tubers] for bacterial ring rot, based on another flare-up of the disease in 2013.
Idaho Crop Improvement Association began offering highly accurate polymerase chain reaction [PCR] testing for ring rot this [2013] spring, after the disease resurfaced as a problem in the 2012 crop [ProMED-mail post 20121004.1322810] following a long absence.
University of Idaho's Phil Nolte predicts the combination of heightened voluntary testing and improved grower sanitation practices will result in a reduction in ring rot next [2014] season.
Ring rot, first reported in the US in the 1930s, is a zero tolerance disease, meaning a single positive plant in a field is cause for rejection of a seed lot. In Idaho, detection also prevents growers from re-certifying seed from any other lots, forcing them to start with new seed after cleaning equipment and buildings.
Commercial potato grower Dan Moss, chairman of the Idaho Potato Commission, believes it may be time for the state to mandate ring rot testing in seed. "What we're doing right now isn't working," he said.
[Byline: John O'Connell]
--
Communicated by:
ProMED-mail
<promed@promedmail.org>
[_Clavibacter michiganensis_ subsp. _sepedonicus_ causes ring rot disease of potato. Yield losses of up to 50 percent have been reported. Many solanaceous species, including tomato and aubergine (eggplant), are also susceptible, and the pathogen has also been found associated with symptomless infections of sugar beet and sugar beet seed.
Symptoms on potato may include wilting and yellowing of leaves, rot of the vascular ring of tubers with emerging bacterial ooze, and extensive tuber rot followed by internal hollowing, cracking, and mummification. Wilting symptoms may occur late in the season and are often masked by the natural senescence of the crop. Symptom expression depends on host cultivar and is favoured by cool climates. Tubers with ring rot are often subjected to secondary invasion by other bacteria and fungi, which can result in total loss of tubers in the field or in storage.
The pathogen is spread with infected seed tubers or other plant material, plant-to-plant contact, soil, and by mechanical means (for example during harvest or grading). The bacteria can survive for several years on dry surfaces and for over a month in water. They can overwinter in unharvested potatoes or crop debris. Ring rot can pass through one or more crop generations without causing symptoms, and latently infected tubers are an important means of spreading the disease. Laboratory tests are needed to detect latent infections.
Disease management is expensive and may include cultural practices and plant hygiene measures before and after harvest, but the use of certified clean seed potatoes is vital. Illegal farm-saved seed potatoes are known to pose a serious risk for the spread of ring rot.
Before 2012, the last flare up of ring rot in Idaho occurred in 2002 (see ProMED-mail post 20121004.1322810) and was managed by phytosanitation during seed cutting and disinfecting equipment and storage facilities.
Maps
USA:
<http://www.mapsofworld.com/usa/usa-state-and-capital-map.html> and <http://healthmap.org/r/2AEB>
Idaho:
<http://www.mapsofworld.com/usa/states/idaho/idaho-map.html>
Pictures
Potato ring rot symptoms:
<http://www.agf.gov.bc.ca/cropprot/images/brr.jpg> (tuber), <http://129.123.92.202/biol5410-kropp/images/Bacterial%20Diseases/Ring%20Rot%20of%20Potato/potato%20ring%20rot,%20late.jpg>
(tuber),
<http://www.agf.gov.bc.ca/cropprot/images/brr-leaf.jpg> (leaf), and via <http://www.forestryimages.org/browse/subimages.cfm?sub=11051> and <http://www.eppo.org/QUARANTINE/bacteria/Clavibacter_m_sepedonicus/CORBSE_images.htm>
Links
Information on potato ring rot:
<http://ohioline.osu.edu/hyg-fact/3000/3103.html>,
<http://www.agf.gov.bc.ca/cropprot/brr.htm>,
<http://www.eppo.org/QUARANTINE/bacteria/Clavibacter_m_sepedonicus/CORBSE_ds.pdf>,
and via
<http://www.potato.org.uk/node/638>,
<http://www.scotland.gov.uk/Topics/farmingrural/Agriculture/plant/18273/PotatoHealthControls/
PotatoQuarantineDiseases/ring/potatoringrotleaflet>,
and
<http://www.fera.defra.gov.uk/plants/plantHealth/pestsDiseases/potatoRingRot.cfm>
Molecular detection of _C. m._ subsp. _sepedonicus_:
<http://apsjournals.apsnet.org/doi/abs/10.1094/PHYTO.1997.87.8.853>
_C. michiganensis_ subsp. _sepedonicus_ taxonomy:
<http://www.uniprot.org/taxonomy/31964>
- Mod.DHA]
[See Also:
Bacterial ring rot, potato - Finland 20130720.1835754 Bacterial ring rot, potato - Chile: (AR) 20130329.1609025 Bacterial ring rot, potato - UK: (England) ex Netherlands, susp.
20130130.1520894
2012
----
Potato diseases - UK, Philippines: incursions susp 20121213.1448960 Bacterial ring rot, potato - USA: (ID) 20121004.1322810 Bacterial ring rot, potato - Netherlands, Germany: update
20120503.1121126
2011
----
Bacterial ring rot, potato - Netherlands (South) 20111229.3697
2010
----
Bacterial ring rot, potato - Canada: (PE) 20101107.4043
2009
----
Potato diseases - UK, USA 20090821.2960
2007
----
Bacterial ring rot, potato - Algeria ex Canada 20071105.3601 and older items in the archives]
Topics
Species
