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: December 31, 2007
Source: ProMED-Plant <promed@promedmail.org>


Total number of ProMED-mail plant posts for 2007: 208

New pathogens: 8

Tomato marchitez virus 20071202.3888
Cyst nematode, maize 20070815.2662
Phytoplasma, palm lethal yellowing group 20070725.2383
Iranian beet curly top curtovirus 20070712.2228
Dioscorea mosaic potyvirus 20070712.2222
Maize redness stolbur phytoplasma 20070607.1844
Al-Wijam disease (date palm) phytoplasma 20070514.1536
Tomato torrado virus 20070324.1030

New strains of known pathogens: 10+

Wheat stem rust, strain Ug99, Kenya variant 20071217.4054
Late blight, potato - UK, multiple strains 20071207.3939
Blackleg, canola - Canada (SK) 20071203.3890
Downy mildew, cucurbits - USA (SC) 20071023.3448
Wheat stripe rust - Australia (SA) 20070921.3135
Wheat leaf rust - UK, multiple strains 20070523.1652
Wheat stripe rust - UK, multiple strains 20070523.1652
Wheat powdery mildew - UK, multiple strains 20070523.1652
_Streptomyces_ common scab, potato - USA (ID) 20070427.1368
_Potato spindle tuber viroid_ - Russia, multiple strains 20070423.1323

First country reports of known pathogens: 33

_Tomato spotted wilt virus_- Jordan 20071223.4123 _Tomato infectious chlorosis virus_ - Jordan 20071223.4123 _Tomato chlorosis virus_ - Turkey 20071215.4030 _Tomato chlorosis virus_ - Mayotte Island 20071215.4030 Phyllody disease, chickpea - Pakistan 20071203.3898 _Tomato yellow leaf curl virus_ - Netherlands 20071128.3837 _Tomato yellow leaf curl Thailand virus_ - Taiwan 20071128.3837 Asian soybean rust - Canada 20071120.3751 _Papaya ringspot virus_ - St. Kitts 20071119.3743 _Tomato torrado virus_ - Poland 20071113.3684:
Brown rot, potato - Ireland 20071022.3438:
_Potato spindle tuber viroid_ - Belgium 20071003.3266 _Verticillium_ wilt, oilseed rape - UK 20071001.3239 _Iris yellow spot virus_ - South Africa 20070920.3129:
_Hop latent viroid_ - China 20070919.3112 Asian soybean rust - Congo DR 20070917.3086 Fireblight, pome fruits - Latvia 20070907.2954 _Plum pox virus_ - Montenegro 20070903.2893 _Plum pox virus_ - Pakistan 20070903.2893 Black pod, cocoa - Puerto Rico 20070831.2865 _Columnea latent viroid_ - UK 20070822.2742 _Tomato chlorotic dwarf viroid_ - UK 20070822.2742 Asian soybean rust - Ghana 20070820.2710 _Banana streak virus_ - Peru 20070810.2601 Orange rust, sugarcane - USA 20070731.2457 Brown stalk rot, maize - South Africa 20070620.1993 Huanglongbing, citrus - Pakistan 20070616.1961 _Beet soil-borne virus_ - China 20070516.1564 _Beet western yellows virus_ - China 20070516.1564 _Cucurbit aphid-borne yellows virus_ - China 20070516.1564 Grapevine leafroll-associated (?) closterovirus-7 - USA 20070502.1424 Fireblight, pome fruit - Morocco 20070321.0990 Wheat stem rust, strain Ug99 - Yemen 20070117.0229

Diseases, crops, and countries

The quantity and quality of information available for ProMED-Plant posts varies considerably within each of these categories. Reports from affluent countries, on high value crops, and on disease problems with a currently high profile are disproportionately more frequent.
Therefore, statistics on the number of reports per disease, crop, or country may be misleading and are not included. Instead, a brief overview of some of the 2007 plant disease issues is provided below.

Selected highlights for the year (in random order)

Wheat stem rust strain Ug99 jumped the Red Sea and spread to Yemen.
An even more virulent variant emerged in Kenya. An international research alliance was formed to screen for resistant germplasm.

Asian soybean rust was first reported in Ghana, the Democratic Republic of Congo, and Canada, and was found in 4 more states in the USA than in 2006.

Banana bacterial (_Xanthomonas_) wilt appears out of control in Africa with a disease focus in Uganda.

Sugarcane smut in Australia has spread to all the major cane growing areas within 18 months of introduction of the pathogen into the country.

Rice viruses and their insect vectors were rampant in parts of Asia.

Cocoa black pod and swollen shoot diseases are causing serious crop losses in West Africa.

Sugarcane orange rust was reported for the 1st time in the Western hemisphere (USA).

Outbreaks of coffee wilt, leaf rust, and berry disease have affected crops in Africa.

Grapevine leaf rust has been successfully eradicated in Australia.

_Banana bunchy top virus_ is re-emerging in Hawaii.

Cassava mosaic disease remains a serious threat to food security in Africa. Resistant germplasm is being distributed to farmers in affected countries.

Potato late blight causes concern in many countries due to emerging new strains with increased virulence and multiple fungicide resistances. A major outbreak has affected crops in India.

A controversy regarding the exclusion of New Zealand pome fruit by Australia to prevent the introduction of fireblight has been taken to the World Trade Organisation.

A breakdown of resistance to lethal yellowing (LY) disease was observed in Malayan Dwarf coconut hybrids. This jeopardises replanting programmes in LY-affected areas. The mechanism of the resistance breakdown is unknown.

Citrus canker and greening (huanglongbing) diseases continue to spread in the USA. Citrus greening was reported for the 1st time from Pakistan. A citrus canker eradication programme is almost complete in Australia.

Fungal diseases of vegetable, cereal and root crops, and also grapevine were of concern in Europe due to warm and humid weather patterns.