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How to manage corn-on-corn
Corn on-corn took some lumps in
2010 and 2011. In some cases, reports of 60 to 70 bushel per acre yield
decreases occurred in Illinois for corn-on-corn vs. corn rotated with soybeans
grown under similar practices in 2011.
Still, growers aren’t giving up
“We used to be in the low 20s
(millions of acres) for corn-on-corn, says Ty Vaughn, U.S. corn product
management lead for Monsanto. “Now, we are pushing 28 million acres of corn-on-corn.”
The boom in planting more corn—USDA’s 95.9 million acre estimate for 2012 is
the highest since 1937—is prompting corn-on-corn acres to grow.
How to do it
Corn-on-corn presents some
challenges compared to corn rotated with other crops. That’s particularly true
after three to five years of continuous corn.
“There’s a buildup of problems like disease, weed, and insect
pressure,” says Vaughn. “Growers also need to focus on Integrated Pest
Management (IPM). IPM is the foundation that you optimize yields with.”
selection is key. Yield potential tops the list of hybrid attributes. Still,
the prolific residue that corn-on-corn brings harbors a great environment for
disease to thrive. That makes disease-resistant hybrids paramount. Ditto for
need a package that can deal with all the environmental stressors that result,”
wilt is a disease once limited to Nebraska and Colorado that’s spreading eastward.
It’s a bacterial disease that overwinters in corn residue. The bacteria can
splash via rain into plants wounded by hail or sandblasted.
best way to manage it is by selecting a hybrid with tolerance to it,” says Luke
Samuel, product development manager at Monsanto.
nematodes are also becoming a threat. These pests, native to North America, thrive
in corn-on-corn. Corn is a grass, and to a nematode, corn is no different than
the native grasses they fed on for centuries.
and plant populations are also crucial factors for successful corn-on-corn. Precision
agriculture is helping farmers better manage fertility and seeding rates.
“Mapping of fields helps farmers know where (N) leaching is going on or where
they can increase plant densities,” says Vaughn.
promising omen for 2012 is the relative dry conditions in many areas that have
enabled farmers to plant corn on time. “We have seen yield decreases (in
corn-on-corn) during a wet spring and when it stays wet,” says Vaughn.
What about rootworm?
2011, cases of corn rootworm that resisted the Cry3Bb1 protein surfaced in some
Midwestern areas. This is the Bt rootworm-resistant trait found in Monsanto’s
YieldGard VT Triple and Genuity VT Triple Pro corn products.
fields planted to these types of hybrids that experienced greater-than expected
corn rootworm damage during 2011, Monsanto gives these following
Rotating to soybeans or another crop. “This can break the rootworm
cycle and enable growers to start fresh the following year,” says Samuel.
Switching to Genuity SmartStax RIB Complete or Genuity SmartStax corn.
These pyramided products feature double modes of action for above-and
below-ground insect protection.
If pyramided products are not available, Monsanto officials recommend a
soil- or foliar-applied insecticide on fields planted with a single action mode
year marks the full-scale launch for Genuity SmartStax RIB Complete with its
95-5% mix of Bt corn with non-Bt corn. Over time, compliance for a separate refuge
had declined. “It is just simpler to have the refuge right in the bag,” says
non-Bt refuge plants are randomly mixed throughout the field. This helps ensure
that any resistant rootworm beetles mate with susceptible ones in order to
prevent them from multiplying.