A
ProMED-mail post
ProMED-mail is a program of the
International Society for Infectious Diseases
A ProMED-mail post
<http://www.promedmail.org>
ProMED-mail is a program of the
International Society for Infectious Diseases <http://www.isid.org>
November 12, 2007
Source: Outlook India, Press Trust of India (PTI) report
[edited]
<http://www.outlookindia.com/pti_news.asp?id=517929>
Potato farmers in Hoshiarpur and Jalandhar are advised to spray
fungicide on their crop as traces of infection of late blight
have been found in some fields in the regions. Recent visits by
scientists of Punjab Agricultural University (PAU) Department of
Plant Pathology to growers' fields in the regions have shown
signs that potato crops may be infected with late blight, a PAU
spokesman said here [Ludhiana] today [12 Nov 2007].
He said cloudy weather and intermittent rain during
November-December favour the rapid development of this disease.
Since the weather is becoming favourable and infected potato
seed has been used at some places, the disease may develop, he
said, adding that the timely protective fungicide spray would
help save the crop from late blight induced losses.
Farmers are advised to immediately go for spraying the crop. It
should be ensured that the foliage be covered completely with
fungicide.
--
Communicated by:
ProMED-mail
<promed@promedmail.org>
[Potato late blight (PLB) is caused by the fungus _Phytophthora
infestans_, which can also infect other solanaceous crops such
as tomato or eggplant. It is one of the most important potato
diseases worldwide and affects leaves as well as tubers. The
fungus is spread by plant material (including seed tubers), wind
and water, and solanaceous weeds can serve as pathogen
reservoirs. Other fungi and bacteria often invade
blight-infected tubers resulting in total tuber breakdown.
Disease management includes preventative fungicide treatments of
seed tubers, but the report above states that this has not been
applied at all locations in the region.
In India, infected seed potatoes are typically the main source
of disease inoculum, and losses of up to 75 percent have been
reported previously in some areas. In the subtropical plains,
conditions favourable for PLB are generally limited, but in the
hills the conditions are highly congenial for the disease.
Several PLB resistant varieties are being deployed around the
country. PLB is considered an increasing problem in India and a
forecasting model has been developed to determine the timing of
fungicide applications.
Worldwide, 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
was 1st recorded in India in the northwestern hills in 1990, and
is also present in northern Europe, northern and Central
America, and parts of Asia. A severe form of PLB 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. New and even more virulent strains continue to
emerge, some of which can destroy a potato plant in a matter of
hours and a complete crop within days.
Maps
India:
<http://www.globalsecurity.org/military/world/india/images/IndiaMap_tourism.gif>
and
<http://healthmap.org/promed?v=22.9,79.6,5>
Punjab:
<http://www.mapsofindia.com/maps/punjab/punjabroads.htm>
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/>,
<http://www.agric.wa.gov.au/pls/portal30/docs/FOLDER/IKMP/PW/PH/DIS/VEG/FS0401_REVIEW.PDF>,
and
<http://www.olympusmicro.com/micd/galleries/brightfield/potatoblight.html>
Potato cultivation and late blight situation in India:
<http://gilb.cip.cgiar.org/index.php?id=1564>
Management of potato diseases including PLB:
<http://archives.eppo.org/EPPOStandards/PP2_GPP/pp2-02-e.doc>
PLB information and resources via:
<http://www.potato.org.uk/department/knowledge_transfer/fight_against_blight/advice_blight.html>
_P. infestans_ taxonomy:
<http://www.indexfungorum.org/Names/SynSpecies.asp?RecordID=232148>
PAU Plant Pathology:
<http://www.pau.edu/departmenthome.asp>.
- Mod.DHA]
[see also in the
archive:
Fungal diseases, vegetable crops - Canada: cucumber, potato
20070730.2442 Late blight, potato & vegetable fungal diseases -
Europe 20070708.2174 Late blight, potato - India, UK
20070509.1491
2006
----
Late blight, potato - India (Kashmir) 20060424.1200 Late blight,
potato - USA (AK), Bangladesh 20060324.0911
2003
----
Late blight, potato - Papua New Guinea 20030306.0554
2002
----
Potato late blight, potato - Canada (Newfoundland) 20020818.5091
2001
----
Phytophthora infestans, potato late blight - Russia
20010620.1177 2000
----
Potato late blight, global research efforts 20001031.1903 Potato
late blight: global initiative 20000516.0765
1996
----
Potato late blight: global threat 19960617.1123] |
|
