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: Fri 13 Mar 2015
Source: FreshPlaza [edited]
<http://www.freshplaza.com/article/136702/Spain-Potato-mildew-fungus-identified-for-first-time>
The Basque Institute for Agricultural Research and Development Neiker-Tecnalia [NT] have identified for the 1st time in Spain genotype Blue13 (13_A2) [of _Phytophthora infestans_]. Blue13 is the most aggressive genotype currently present in Europe and has been detected in the provinces of Alava, Orense and Tenerife.
NT have also identified 2 variants called Misc from Alava and Cadiz.
These do not match any other type described to date in Europe, which could mean that they are the result of sexual recombination of the 2 existing mating types (A1 and A2). This would entail a significant change in the epidemiology of the pathogen in Spain.
NT have been detecting new physiological types of the pathogen in recent years with previously unobserved aggressiveness and resistance to the fungicides currently used. It is also noted that new types are adapting to weather conditions, allowing them to expand their range.
These changes in the populations of _P. infestans_ should lead to greater efforts in the development of new resistant potato varieties.
Early warning systems are necessary [and] it is essential to combine active ingredients to prevent the emergence of resistance.
NT will continue [surveying] to complete the map of all production areas in Spain. It also aims to extend the study to tomatoes, another major host for the pathogen.
--
Communicated by: ProMED-mail <promed@promedmail.org>
[Potato late blight (PLB) is caused by the fungus-like organism
(oomycete) _Phytophthora infestans_ and can cause 100 per cent crop loss. The pathogen can also affect tomato and some other solanaceous crops. In potato, it affects leaves as well as tubers, and in tomato, it causes lesions and rotting of leaves, stems and fruits. The disease is favoured by cool, moist conditions. It can spread rapidly within a crop and destroy it within a few days. Under favourable conditions, epidemics in tomatoes may be even more rapid than in potatoes.
PLB is spread by plant material (including plant debris and volunteer crop plants), mechanical means (including human and insect activities), wind and water. Disease management requires an integrated approach and may include removal of pathogen reservoirs, crop rotation, preventive fungicide treatments of planting material and fungicide sprays of crops. Farm-saved or uncertified seed tubers have often been reported as sources of PLB outbreaks and seed tuber certification schemes have been set up in many countries. Clean planting stock and management strategies for fungicide resistance of the pathogen are vital. Development of resistant cultivars is being counteracted by the adaptability of the pathogen.
Late blight is considered an increasing problem worldwide.
Considerable variation in aggressiveness between different pathogen strains has been observed, but more virulent strains are emerging frequently. Where both A1 and A2 mating types of the pathogen are present, reproduction occurs sexually as well as asexually, increasing the chances of strains with additional fungicide resistances and increased yield losses to develop (such as the 2 misc variants mentioned above). All blight outside Mexico was A1 until in 1976 when potatoes were imported into Europe from Mexico to satisfy shortages.
Soon after A2 strains were detected in Europe.
It has been reported that regional differences in pathogen population diversity no longer exist in Europe, where strains like the particularly aggressive A2-Blue13 (EU_13_A2; ProMED-mail posts
20090406.1332 and 20100212.0505) as well as Pink6 (ProMED-mail post
20100604.1851) are now dominating, and further strains, such as
Green33 (ProMED-mail post 20120202.1031230), are emerging. The arrival of Blue13 in Spain poses a risk of additional crop losses and increased costs of PLB control for the national potato industry.
Furthermore, while the incidence of A2 strains has increased over time, the incidence of mixed A1/A2 strains which is used as an indicator of genetic recombination frequencies appears to have remained constant until now (ProMED-mail post 20071207.3939).
Therefore, the detection of 2 additional novel strains, as reported above, with mixed A1/A2 parentage is particularly worrying and increases the threat of PLB to potato production for European countries and their trading partners.
Maps
Spain:
<http://www.map-of-spain.co.uk/large-map-of-spain.htm>
Provinces & Communities of Spain:
<http://www.data-spain.com/map.html>
Europe, overview:
<http://www.edinphoto.org.uk/0_MAPS/0_map_europe_political_2001_enlarged.jpg>
Pictures
Late blight on potato:
<http://www.potatomuseum.com/images/exblightfieldwithinsert.jpg> and <http://farm1.static.flickr.com/81/281344513_74bbffe5fe.jpg>
Potato variety trials for PLB resistance:
<http://phys.org/news/2012-09-uw-scientists-probe-late-blight.html>,
<http://www.sarvari-trust.org/assets/images/phil%20img_4682%20lg%281%29.jpg>
and
<http://cdn.phys.org/newman/gfx/news/2013/keepingpacew.jpg>
Late blight on tomato:
<http://ipm.illinois.edu/ifvn/volume15/images/tomato_late_blight.jpg>
Microscopy of PLB infected cells:
<http://micro.magnet.fsu.edu/optics/olympusmicd/galleries/brightfield/images/potatoblight.jpg>
Links
Additional news story:
<http://www.potatopro.com/news/2015/neiker-tecnalia-detects-blue13-genotype-phytophthora-infestans-spain>
Information on late blight:
<http://ohioline.osu.edu/hyg-fact/3000/3102.html>,
<http://vegetablemdonline.ppath.cornell.edu/factsheets/Potato_LateBlt.htm>
and
<http://www.apsnet.org/edcenter/intropp/lessons/fungi/Oomycetes/Pages/LateBlight.aspx>
PLB disease cycle:
<https://research.cip.cgiar.org/confluence/download/attachments/37192494/4f888c445a.jpg?version=1&modificationDate=1274541183000&api=v2>
PLB information, A2 strains and emergence of Blue 13 in UK:
<http://www.sarvari-trust.org/late-blight.html>,
<http://www.pestalert.org/viewNewsAlert.cfm?naid=71>,
<http://academy.fwi.co.uk/Courses/Arable/Potato-pests-and-diseases/Potatoes-Understanding-blight>
and
<http://www.scri.ac.uk/research/pp/pestanddisease/blightepidemiologyandpopulationbiology>
Blue13 distribution in Europe via:
<http://euroblight.net/fileadmin/euroblight/Monitoring_2013_project/Potato_Blight_Mapped_in_Europev2.pdf>
Late blight information and resources via:
<http://euroblight.net/>
_P. infestans_ taxonomy:
<http://www.indexfungorum.org/Names/NamesRecord.asp?RecordID=232148>
Global Initiative on Late Blight:
<https://research.cip.cgiar.org/confluence/display/GILBWEB/Home>
Neiker Tecnalia:
<http://www.neiker.net/?lang=en>
- Mod.DHA
A HealthMap/ProMED-mail map can be accessed at:
<http://healthmap.org/promed/p/43>.]
[See Also:
Late blight, potato - Nepal: (DN) 20150128.3127014
2014
----
Late blight, potato - Nigeria, UK 20140611.2533396 Late blight, potato & tomato - Canada: strains 20140428.2434165 Late blight, potato - Bangladesh: (KH) 20140320.2345850
2013
----
Late blight, tomato - Oman: (BS) 20130603.1752356 Yellow leaf curl & blights, tomato - Pakistan: (SD) 20130206.1531086 Late blight, potato: new strains threat 20130111.1492024
2012
----
Late blight, potato - UK: strain Green 33 20120202.1031230
2010
----
Late blight type A2, potato - Estonia: 1st report 20101129.4298 Late blight, potato - Ireland: strain Pink 6 20100604.1851 Dickeya, leaf blights, potato - UK, Ireland 20100528.1775 Late blight, potato - Ireland: strain Blue13 20100212.0505
2009
----
Potato diseases - UK, USA 20090821.2960
Late blight, potato - UK: sources 20090427.1592 Late blight, potato - Algeria: update 20090420.1490 Late blight, potato - UK, Bangladesh 20090406.1332
2008
----
Late blight type A2, tomato - Taiwan: 1st report 20080615.1891 Late blight, potato - UK: (Scotland), alert 20080430.1482
2007
----
Late blight, potato - UK: new strains 20071207.3939 Late blight, potato & vegetable fungal diseases - Europe
20070708.2174
and additional items on late blight in the archives]
Topics
Species
