A ProMED-mail post
<http://www.promedmail.org>
ProMED-mail is a program of the
International Society for Infectious Diseases <http://www.isid.org>
Wed 11 Feb 2009
Source: Prensa Libre [in Spanish, trans. Rappt.SB, edited] <http://www.prensalibre.com/pl/2009/febrero/11/294505.html>
Fungus causing losses in maize yields
Maize is the staple diet for thousands of Guatemalans. Farmers
of Alta Verapaz, Quiche, and Peten have been hit since last
December [2008] by a fungus called 'slick asphalt', which
blackens maize crops, reported the National Basic Grains
Commission (Conagrab).
The president of Conagrab, Alberto Ical, said that crop losses
of up to 75 per cent due to this fungus have been reported in
Chisec, Alta Verapaz, and La Chapina, Quiche, where maize
production of 30 000 and 40 000 quintals [3000 and 4000 tonnes],
respectively, had been estimated. Outbreaks of the disease have
also been detected in Sayaxche, Peten, with estimated crop
losses of 50 per cent, Ical added.
Edgar Grisolia, deputy minister of agriculture, confirmed the
appearance of the fungus in maize and said he ordered an
investigation to determine the origin of the problem and how to
fight it. In any event, he explained, farmers were provided with
fungicides and some spray pumps. "We can defeat (the disease),
but if there are losses it is because they did not apply it (the
fungicide) correctly," the official said. The deputy minister
said that for now, there is no shortage of grain in the market,
and that, if necessary, the import quotas opened by the Ministry
of Economy would be used.
A group of researchers at the Institute of Agricultural Sciences
and Technology (ICTA) and others visited Ixcan, Quiche, to
determine the details of the problem, reported Oscar Salazar,
technician at this institution. The appearance of the fungus was
reported in April 2007, when it destroyed maize plantings in
areas of Peten. Losses were estimated at 60 per cent of local
production. According to Salazar, the spread in the country is
already cause for alarm. Grisolia and Salazar agreed that one
way to prevent this and other diseases of maize is the use of
improved seed.
The disease occurs in cool and humid conditions. Spots first
appear on the lower leaves before flowering. Lesions may merge
causing complete necrosis of foliage. Lumps of deep black colour
are formed. The disease does not allow the ears to develop
properly leading to poor quality grain. Only small kernels are
produced, and those at the tip of the ears germinate
prematurely.
[byline: Rosa Maria Bolanos]
--
communicated by:
ProMED-mail rapporteur Susan Baekeland
[There are a large number of fungal pathogens that can affect
maize. From the description of symptoms, especially the 'black
lumps', perhaps a form of smut may be implicated. We would be
most grateful for any information as to what this disease may
be.
Maps
Guatemala:
<http://www.lib.utexas.edu/maps/americas/guatemala_pol00.jpg>
and
<http://healthmap.org/promed/en?g=3590964&v=15.5,-90.917,6>
Departments of Guatemala:
<http://www.guatemalaguides.com/about-guatemala/map-of-guatemala-by-departments.php#>
Pictures of several fungal symptoms on maize via:
<http://maizedoctor.cimmyt.org/index.php?option=com_easygallery&act=categories&cid=325&Itemid=33>
Links
Information and identification of common maize diseases via:
<http://maizedoctor.cimmyt.org/index.php>
List of diseases and pathogens of maize:
<http://www.apsnet.org/online/common/names/corn.asp>.
- Mod.DHA]