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[1] Late blight, potato - Europe
[2] Late blight, potato and fungal diseases, vegetable crops - UK
[3] Late blight, potato - UK

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[1] Late blight, potato - Europe
Date: 5 Jul 2007
Source: Earth Times [edited]
<http://www.earthtimes.org/articles/show/79626.html>

Wet and warm growing conditions could mean trouble for the potatoes across Northern Europe. Potato blight is reported as being widespread, and the situation without some dry weather could be disastrous for this season's [2007] potato crop.

Potatoes in the UK, Holland, Germany, Belgium and France are said to be the worst affected, with some main crop potato fields already desiccated. Some Eastern European crops have also been hit according to industry experts, although lack of information from this area means that it is difficult to establish to what extent blight has taken hold.

There are also industry reports that blight spray is running scarce, with only limited quantities available, meaning that spraying regimes cannot be followed by all growers. This shortage of blight spray is said to be Europe-wide.

In parts of the UK, floods over the past 3 weeks have also immersed some fields for over 48 hours, rendering the potato crop useless.
This has affected several hundred acres, and the full extent of UK flood damage is yet to be known.

The weather across Northern Europe will surely have an affect on medium to long term potato availability and prices; short term storage problems could well be the biggest issue, as they were with last year's [2006] potato crop in Europe. Last season's storage problems were due to late rains throughout August and September.

The rain over the past 5 weeks in Europe has been continuous and, combined with warm temperatures, has started a potential blight catastrophe, which may not have been seen for decades.

[Byline: Ryan Jones]

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Communicated by:
J. Allan Dodds
Former ProMED-mail plant disease moderator <dodds@ucr.edu>

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[2] Late blight, potato and fungal diseases, vegetable crops - UK
Date: 5 Jul 2007
Source: British Broadcasting Corporation News [edited] <http://news.bbc.co.uk/2/hi/uk_news/6271584.stm>


Potato blight is spreading, following the recent wet weather, the National Farmers' Union (NFU) has warned. Farmers have been unable to spray their crops to protect them from the fungal disease, which causes plants to rot.

NFU horticulture board chairman Richard Hirst said that if there is a crop in the country that does have the potato blight "it is a miracle. The problem is that conditions are so wet that crops are full of these diseases," he said. Mr. Hirst said the land on his farm in Norfolk was the wettest it had been for 25 years. He said fewer customers were going to pick-your-own farms, and salad growers were experiencing less demand.

The NFU said cabbages, cauliflower, broccoli and other vegetables were also suffering in the conditions. The Processed Vegetable Growers Association has previously said frozen pea prices may rise, because a quarter of the crop could have been destroyed.

The Food and Drink Federation's (FDF) Frozen Vegetable Committee warned of a "disastrous" pea harvest, with a crop output of 70 percent, a figure that is falling every day with the rains continuing. Sarah Pettitt, chairman of the committee, said: "Other crops such as broad beans, green beans and brassicas are also being seriously affected, particularly broad beans and the potential green bean crop, where in certain parts of the country we have only 25 percent drilled."

The British Retail Consortium has also said sales of salad produce, some soft fruit, and barbecue food, such as burgers and sausages, had all been hit.

--
Communicated by:
J. Allan Dodds
Former ProMED-mail plant disease moderator <dodds@ucr.edu>

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[3] Late blight, potato - UK
Date: 28 Jun 2007
Source: Farmers Guardian [edited]
<http://www.farmersguardian.com/story.asp?sectioncode=19&storycode=10847>


There is an increasing amount of blight occurring in potato crops across the UK following the recent wet and warm conditions. "As a result of all the Smith Period pressure [see Mod. comment below] we have had for the last few weeks, we are now certainly seeing the highest level of blight incidence reporting since we started the Fight Against Blight campaign 5 years ago," said British Potato Council (BPC) knowledge transfer manager, Rob Clayton.

"There is no doubt that blight is at higher levels than we would normally see at this time of year, and this is the earliest and fastest we have seen blight spread for a long time, which paints a worrying picture."

On Wednesday [27 Jun 2007], the BPC were already aware of over 80 blight incidences around the country, with hotspots reported in East Anglia and the Midlands in addition to Cornwall and the South West.
"More recently, the disease has been creeping up into the North West and Cheshire; however, it appears to be not as bad north of the Humber at the moment."

The increased blight incidence was, he said, due to a combination of the recent wet and mild conditions together with growers' inability to travel on wet fields.

[Byline: Joanna Baker]

--
Communicated by:
J. Allan Dodds
Former ProMED-mail plant disease moderator <dodds@ucr.edu>

[Potato late blight is caused by the fungus _Phytophthora infestans_, which can also infect other solanaceous crops such as tomato or eggplant. It affects leaves as well as tubers and is spread by plant material (including seed tubers), wind and water. Other fungi and bacteria often invade blight-infected tubers resulting in total tuber breakdown. Considerable variation in aggressiveness between different isolates of _P. infestans_ has been observed. There are 2 mating types, A1 and A2. Where both are present, reproduction occurs sexually as well as asexually, leading to greater variation and fitter strains with higher fungicide resistance and increased yield losses. A1 occurs worldwide; A2 is recorded in Mexico, northern Europe, Japan, Korea, Indonesia and northern America.

_P. infestans_ was responsible for the Irish potato famine in the late 1840s, which resulted in large-scale population loss from that country due to deaths and emigration. For more information on potato late blight, see also the recent post with archive no. 20070509.1491.

Species in the genus _Phytophora_ often have a narrow host range, and many cause serious diseases in a range of crops. Different species of _Phytophthora_ (possibly _P. phaseoli_ or _P. brassicae_) or species in other fungal genera may be responsible for the diseases reported in item [2] affecting the legumes (peas, beans) and brassicas (cabbage varieties).

Smith Periods are whether patterns used to predict the risk of potato late blight. They were developed empirically by identifying the relationship between specific weather criteria and disease development. A full Smith Period has occurred when at least 2 consecutive days have had a minimum temperature of 10 C or above and when on each day for at least 11 hours, the relative humidity was more than 90 percent. These conditions are conducive for sporulation and ideal for the pathogen. If they occur in 7-10 day intervals, there is a greater chance of blight development, because this is the generation time from original infection to lesion development and, finally, sporulation.

Maps
Europe:
<http://www.edinphoto.org.uk/0_MAPS/0_map_europe_political_2001.jpg>
UK:
<http://www.lib.utexas.edu/maps/europe/united_kingdom.gif>
Location of East Anglia:
<http://en.wikipedia.org/wiki/East_Anglia>

Pictures
Diseased potato tubers:
<http://www.sciencedaily.com/images/2007/01/070102132649.jpg>
Leaf symptoms:
<http://www-biol.paisley.ac.uk/bioref/Chromista/potato_blight.jpg>
Microscopy of infected cells:
<http://micro.magnet.fsu.edu/optics/olympusmicd/galleries/brightfield/images/potatoblight.jpg>
Microscopy of sporangiophores:
<http://www-biol.paisley.ac.uk/bioref/Chromista/Phytoph_infestans.jpg>

Links:
Disease information, history and background:
<http://www.apsnet.org/online/feature/lateblit/>  and <http://www.agric.wa.gov.au/pls/portal30/docs/FOLDER/IKMP/PW/PH/DIS/VEG/FS0401_REVIEW.PDF>
Blight advice and information resources:
<http://www.potato.org.uk/department/knowledge_transfer/fight_against_blight/advice_blight.html>
Explanation of Smith periods for disease prediction:
<http://www.blightwatch.co.uk/content/bw-Smith.asp>
_P. infestans_ taxonomy:
<http://www.indexfungorum.org/Names/SynSpecies.asp?RecordID=232148>
Taxonomic list of genus _Phytophthora_ via:
<http://www.indexfungorum.org/Names/Names.asp>
British Potato Council:
<http://www.potato.org.uk>
Blightwatch UK:
<http://www.blightwatch.co.uk>
- Mod.DHA]

[see also in the archive:
Late blight, potato - India, UK 20070509.1491
2006
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Late blight, potato - India (Kashmir) 20060424.1200 Late blight, potato - USA (AK), Bangladesh 20060324.0911
2003
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Late blight, potato - Papua New Guinea 20030306.0554
2002
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Potato late blight, potato - Canada (Newfoundland) 20020818.5091
2001
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Phytophthora infestans, potato late blight - Russia 20010620.1177 2000
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Potato late blight, global research efforts 20001031.1903 Potato late blight: global initiative 20000516.0765
1996
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Potato late blight: global threat 19960617.1123]

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