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Published Date: 2017-05-15 22:46:03
Subject: PRO/PL> Leaf rust, coffee - Honduras: new strain susp.
Archive Number: 20170515.5038218
LEAF RUST, COFFEE - HONDURAS: NEW STRAIN SUSPECTED
**************************************************
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 12 May 2017
Source: Daily Coffee News [edited]
http://dailycoffeenews.com/2017/05/12/popular-honduras-variety-lempira-found-susceptible-to-leaf-rust/


World Coffee Research [WCR] has confirmed that the Lempira coffee variety is no longer resistant to leaf rust. This confirms the industry's worst fear since outbreaks were reported earlier this year [2017] in important Honduran coffee-producing regions.

"Lempira, makes up a significant portion of Honduran coffee and has been widely planted since an epidemic of leaf rust hit Central America beginning in 2012," WCR said. Rust infections [were reported] in January 2017. WCR conducted DNA fingerprinting, confirming that Lempira is indeed now susceptible to rust. According to the national coffee institute (IHCAFE), 18 per cent of Lempira farms surveyed in March [2017] had an incidence level higher than 10 per cent.

One [possibility] is that a rust race present in Honduras may have overcome Lempira's resistance. It is also possible that a race not previously present has moved into the region. Researchers and breeders have been concerned for years about both possible scenarios. Rust spores have been sent for identification, but results are not expected until August 2017.

There are dozens of rust races that affect coffee globally. Historically, the predominant races in Central America have been races I and II. There is no [coffee] variety that is resistant to all races. WCR is checking its 24-country International Multilocation Variety Trial to determine if Lempira is affected in countries other than Honduras.

[Byline: Nick Brown]

--
Communicated by:
ProMED-mail
<promed@promedmail.org>

[Coffee leaf rust (CLR; also called orange rust) is caused by the fungus _Hemileia vastatrix_, one of the most feared pathogens of the crop. Of the 2 coffee species grown commercially, _Coffea arabica_ (arabica or highland coffee) and _C. canephora_ (robusta or lowland coffee), it affects only arabica varieties, which are usually preferred for their taste. The rust has completely destroyed coffee industries in several countries. The disease is characterised by yellow-orange powdery lesions on the underside of leaves, where it attacks through stomata, but it rarely occurs on stems or fruit. CLR can lead to complete defoliation with death of the host plant.

Fungal spores are spread by wind, rain and mechanical means. Disease management relies mainly on multiple fungicide applications during the rainy season. Rust-resistant cultivars exist, but the crop is generally of poorer quality. More than 30 races of the fungus have been detected, making it particularly difficult to establish durable host resistance.

New fungal strains adapted to higher altitude conditions, which may also show additional fungicide resistances, have emerged in Central America, making CLR control in the region considerably more difficult (for example, see ProMED-mail post 20120920.1301244). Central America, including Honduras, mostly produce arabica beans.

Maps
Honduras:
http://www.worldatlas.com/webimage/countrys/namerica/camerica/lgcolor/hncolor.htm
Honduras departments:
http://www.zonu.com/mapas_honduras/m_onu_hondurasx.htm
Central America, overview:
http://www.worldatlas.com/webimage/countrys/namerica/camerica/printpage/camerica.htm
Early worldwide spread of coffee rust (pre-1990):
http://www.apsnet.org/edcenter/intropp/lessons/fungi/Basidiomycetes/Article%20Images/CoffeeRust01.jpg

Pictures
CLR leaf symptoms:
http://santaram09.files.wordpress.com/2010/01/coffee-leaf-rust.jpg
CLR affected coffee plant:
http://dwpicture.com.au/photos/110363b.jpg

Links
Additional news story:
http://dailycoffeenews.com/2017/05/08/coffee-leaf-rust-rears-its-ugly-head-again-in-honduras/
Coffee rust information and background:
http://www.extento.hawaii.edu/kbase/crop/Type/h_vasta.htm,
http://www.apsnet.org/edcenter/intropp/lessons/fungi/Basidiomycetes/Pages/CoffeeRust.aspx,
http://www.coffeeresearch.org/agriculture/hemileiavastatrix.htm and
http://www.nature.com/news/coffee-rust-regains-foothold-1.12320
CLR resources:
http://www.coffeeresearch.org/agriculture/rust.htm
_H. vastatrix_ taxonomy:
http://www.speciesfungorum.org/Names/NamesRecord.asp?RecordID=182962
Arabica coffee varieties:
http://www.coffeeresearch.org/agriculture/varietals.htm
World Coffee Research:
https://worldcoffeeresearch.org/
- Mod.DHA

A HealthMap/ProMED-mail map can be accessed at: http://healthmap.org/promed/p/22.]

See Also

2016
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Leaf rust, coffee - Nepal 20160119.3947313
2015
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Leaf rust, coffee - Mexico 20150309.3216608
2014
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Leaf rust, coffee - Peru: alert 20141027.2904184
Leaf rust, coffee - Central America: high altitude strain, update 20140604.2518313
Leaf rust, coffee - Mexico: (CP) high altitude strain 20140128.2236486
2013
---
Leaf rust, coffee - Panama: 1st rep 20130527.1738972
Leaf rust, coffee - Guatemala: emergency 20130203.1527736
2012
---
Multiple fungal diseases, coffee - Nicaragua: (JI, MT) 20121128.1429421
New leaf rust strain, coffee - Central America: update 20120920.1301244
Leaf rust, coffee - Guatemala: new strain 20120511.1129720
Leaf rust, coffee - Dominican Rep: (BH) 20120126.1023078
and older items in the archives
.................................................sb/dha/msp/ml
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