Honduras, TAR SPOT, MAIZE: SPREAD

Disease known as “tar spot” threatens maize in Honduras
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The Ministry of Agriculture and Livestock called for urgent
cooperation in fighting a disease known as “tar spot” which is
decimating white maize. The disease is attacking the fields of small
farmers with more than 30 per cent of their crops affected.

In Honduras this disease was detected 4 years ago and over time has
spread to most of the country, but the departments most affected are
Comayagua, El Paraiso, and Olancho.

The deputy agriculture minister Juan Angel Artica, said, “We will
validate the work being done on combinations of [agrochemicals].” A
representative of agribusiness said they are willing to cooperate with
the government in combating this disease.

[byline: Faustino Ordonez]

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[Tar spot of maize is a disease complex, which has been known to
cause serious yield losses of up to 75 per cent in Central and South
America. It is caused by the association of at least 3 fungal species:
_Phyllachora maydis_, _Monographella maydis_, and _Coniothyrium
phyllachorae_.

Of these, _P. maydis_ is usually the first to cause leaf lesions.
While _M. maydis_ is a common benign saprophyte on leaf surfaces, it
becomes highly virulent only in association with _P. maydis_ and forms
necrotic rings around the _P. maydis_ lesions. _C. phyllachorae_ may
be a hyperparasite of the other 2, but its role is not fully
understood yet. Leaf lesions may coalesce causing blight and complete
burning of the foliage. In addition, characteristic black, shiny spots
(“tar spots”) are produced both within lesions and on other leaf
areas. Affected ears have fewer kernels which may germinate
prematurely on the cob.

_P. maydis_ is an obligate parasite, its spores are spread by wind,
and it produces a potent toxin killing plant tissue. The disease is
favoured by cool, humid conditions. Disease management relies mainly
on the use of resistant maize varieties, however little is known about
the genetics of tar spot resistance.

Archive Number 20110210.0456
Published Date 10-FEB-2011
Subject PRO/PL> Tar spot, maize – Honduras: spread

TAR SPOT, MAIZE – HONDURAS: SPREAD
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