Coping With Moldy Corn
COLUMBIA, MO.
Farmers can cope with mold-ridden corn in
fields and bins in a few ways. “If you still
have corn in the field, the most important
thing is to harvest as quickly as possible,” said
Laura Sweets, University of Missouri Extension
Commercial Agriculture plant pathologist.
“Farmers have been docked pretty badly when
taking loads into the elevators because of high
moisture content or a lot of mold, either of
which may lower test weight.”
Two types of mold present a particular problem
this year where wet fields measure moisture
content of more than 20 percent: Diplodia – a
dense white to grayish-white mold that mats between
kernels and husks – and fusarium/gibberella
– a whitish-pink to reddish-pink mold
that typically starts at the tip of the ears and
progresses down – are both prevalent in many
corn fields. To prevent continued mold growth
when grain is in storage, moisture needs to stay
below 15 percent.
Sweets noted that adjusting combines correctly
could help keep some moldy matter out
of hoppers and grain bins.
“A lot of the time the kernels that have ear and
kernel rot are lighter and may be shrunken, so
if you adjust the fans a little bit you can blow a
lot of that out to keep it out of the hopper, the
truck and the storage bin,” Sweets said.
Running combines at full capacity with concave
settings open, cylinder speed set low and
fan speeds elevated can help blow out cob
pieces and fines, which generally contain more
spores and mold.
Once in the bin, the focus switches to aeration
and drying of corn. Aeration helps to maintain a
cool, uniform temperature throughout bins to
reduce mold growth.
Charles Ellis, MU Extension natural resource
engineer in Lincoln County, explains that moisture
migration can exacerbate mold problems in
winter. As temperatures drop, warm air can rise
in the center of the bin, cooling when it reaches
the cold grain near the surface. This results in
moisture condensation, leading to rapid
spoilage when spring brings higher temperatures.
Concern about mold should not stop at the
bin.
Sweets said proper crop rotation is important
to prevent repeat problems.
“The fungus survives in the cob tissue, some
of the stalk tissue and some of those lightweight
kernels blown out in harvest,” Sweets said. “So
if a person had a high level of diplodia this last
year, crop rotation is a must as they plan their
acres for 2010.” Δ