Amaru=ill, Texas
February 11, 2009
Fungal infections in seed are not
normally a problem under the High Plains’ dry weather
conditions, but they can still occur, a
Texas AgriLife
Extension Service specialist said.
Both producers and grain elevator operators need to be vigilant
in their watch for contaminated seed and make sure treatment
occurs before the seed from one year's harvest is replanted the
following year, said Dr. Ron French, AgriLife Extension plant
pathologist.
French spoke at the Texas High Plains Grain Elevator Workshop in
Amarillo. He told the elevator operators seed quality remains
one of the top issues in stored grains as it relates to seedling
diseases and future diseases wheat might face if the grain is
used for planting.
There are several fungi that can attack cereal grains, he said.
Some of these fungi can cause black point (kernel smudge),
stinking smut (common bunt), and other secondary rots which can
slowly degrade grain seed if improperly stored.
The seed can be infected with the fungi pre-harvest if the crop
was subjected to stresses such as drought, insect damage,
moisture, wind damage and other conditions that favor plant
disease development, French said.
“Even if seed is properly cleaned, some affected seed might
escape the cleaning process,” he said.
Seed containing certain fungi can suffer from damping-off, root
or crown rot at the seedling stage, French said. Some fungi can
become a problem later on in the season if the seedling
survived.
“There are several fungi that can cause such rots, but they also
can be managed with seed treatments,” he said. “If you’ve had a
history of soil-borne pathogens in your field, such treatment
might be warranted.”
Fungi may also become a problem in storage facilities if there
was a history of seed contamination and/or the storage unit had
not been properly cleaned, French said. The right temperature
and moisture conditions must be maintained in the grain
elevators to prevent fungi from being active against the seeds.
“Under the right conditions, fungal spores can germinate and
infect the seed during storage, causing moldy or rotted seeds,”
he said. But generally there are few fungal problems seen at the
elevator level.
In addition to affecting the performance of the crop, the fungi
are a concern because some can produce toxins that affect both
humans and animals, French said. Good seed quality and storage
conditions are important in preventing such toxins from
occurring at unacceptable thresholds.
“The healthier the crop, the less chance for it to be
susceptible to fungal pathogens and their by-products,” he said.
“If you are a producer who had problems with sooty molds,
stinking smut, black point, kernel rots and other seed rots, you
should probably use a fungicide seed treatment before using that
seed again.
“If you are worried about your own seed quality, you might also
want to look into the possibility of purchasing certified seed,”
French said. |
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