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: Mon 10 Jun 2024
Source: Proplanta [in German, trans. & summ. Mod.DHA, edited]
https://www.proplanta.de/agrar-nachrichten/pflanze/krautfaeule-bedroht-
kartoffelanbau-in-europa_article1718020224.html


The German unions of farmers (Deutscher Bauernverband) and of potato producers (Union der Deutschen Kartoffelwirtschaft) consider potato production in Europe to be under severe threat due to late blight. They warn that the risk of massive outbreaks is bigger than it has been for a long time.

Particularly in Denmark and the Netherlands, there have recently been veritable epidemics with considerable economic damage. The reason is considered to be the use of only a few approved fungicides and their reduced amounts, resulting in the enforced neglect of the necessary resistance management. The national potato industry cannot afford to repeat any mistakes of their neighbours.

It is vital to prevent the emergence and fast spread of new pathogen strains with additional new fungicide resistances throughout Europe. To achieve this, a collaboration between countries in the region is
necessary with the aim of developing late blight control strategies for the future. These need to include equal parts of phytosanitary measures to prevent crop infections, effective agrochemicals, as well
as breeding programmes for late blight resistant crop varieties to prevent both crop loss and development of new pathogen strains.

--
Communicated by:
ProMED

[Late blight of potato (PLB) and tomato is caused by the fungus-like organism (oomycete) _Phytophthora infestans_ and can cause 100% crop loss. The pathogen can also affect some other solanaceous crops. In potato, it affects leaves as well as tubers; 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.

The pathogen is spread by plant material (including potato seed tubers, tomato transplants, plant debris, volunteer crop plants), mechanical means (including human and insect activities), wind and
water. Disease management requires an integrated approach; it may include removal of pathogen reservoirs, crop rotation, preventative fungicide treatments of planting material, as well as fungicide sprays of crops. Farm saved or uncertified seed tubers have often been reported as sources of PLB outbreaks. Certified clean planting stock and management strategies for fungicide resistance of the pathogen are considered vital to control late blight outbreaks. Commercial crop cultivars vary in susceptibility to late blight. 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. The presence of both A1 and A2 mating types of the pathogen increases the chances of strains with additional fungicide resistances and increased yield losses developing.

Pictures
Late blight on potato:
https://onvegetables.com/wp-content/uploads/2018/08/Potato-late-blight-No-halo.jpg,
https://www.thompson-morgan.com/static-images/tandm/static-articles/how-to-stop-potato-blight/what-is-potato-blight.jpg
and
https://farm1.static.flickr.com/81/281344513_74bbffe5fe.jpg
Late blight on tomato:
http://ipm.illinois.edu/ifvn/volume15/images/tomato_late_blight.jpg
Microscopy of PLB infected cells:
https://micro.magnet.fsu.edu/optics/olympusmicd/galleries/brightfield/images/potatoblight.jpg

Links
Additional news story (in German):
https://www.proplanta.de/agrar-nachrichten/pflanze/auf-pilzkrankheiten-in-kartoffeln-
achten_article1718248262.htmlkartoffeln-achten_article1718248262.html
PLB information with time lapse of PLB symptom development vs. healthy
plant:
https://www.agroscope.admin.ch/agroscope/de/home/themen/pflanzenbau/ackerbau/kulturarten/kartoffeln/krankheiten/kraut-knollenfaeule.html
(incl. disease cycle)
Information on late blight:
https://gd.eppo.int/taxon/PHYTIN (with photo gallery),
https://doi.org/10.1079/cabicompendium.40970,
https://cropscience.bayer.co.uk/threats/diseases/potato-diseases/late-blight/,
https://cipotato.org/press_room/blogs/combating-late-blight/ and
https://www.gov.mb.ca/agriculture/crops/plant-diseases/print,mgmt-late-blight-potatoes.html

_P. infestans_ taxonomy & synonyms:
http://www.indexfungorum.org/Names/NamesRecord.asp?RecordID=232148
and
https://www.speciesfungorum.org/GSD/GSDspecies.asp?RecordID=232148
- Mod.DHA]

[See Also:
Late blight, potato - Switzerland
http://promedmail.org/post/20240530.8716771
Late blight, potato - Jordan: alert
http://promedmail.org/post/20240306.8715232
2023
----
Late blight, potato - India: (PB)
http://promedmail.org/post/20231219.8713807
Late blight, potato - UK: fungicide resistances Archive Number:
http://promedmail.org/post/20230126.8707982
2022
----
Late blight, potato - Nigeria: (PL)
http://promedmail.org/post/20220719.8704518
Late blight, potato - Nepal: (KN)
http://promedmail.org/post/20220203.8701230
2021
----
Late blight, potato - Europe, Asia: population changes
http://promedmail.org/post/20210507.8349166
2020
----
Late blight, potato - Russia: (SL)
http://promedmail.org/post/20200820.7696987
Late blight, potato - Ireland, UK: alert
http://promedmail.org/post/20200618.7481853
Late blight, potato - India: (PB)
http://promedmail.org/post/20200113.6887703
Late blight, potato - Africa: strain 33_A2, 1st rep (Nigeria)
http://promedmail.org/post/20200103.6868372
2019
----
Late blight, potato - Europe (02): UK, strain 36_A2
http://promedmail.org/post/20190712.6562717
Potato diseases - Russia: survey
http://promedmail.org/post/20190606.6506616
Late blight, potato - Europe: emerging strains
http://promedmail.org/post/20190416.6424462
Late blight, potato - Nigeria: (PL)
http://promedmail.org/post/20190130.6286551
and additional items on late blight in the archives]

Website: http://www.isid.org

Published: July 8, 2024