Nashville, Tennessee
March 4, 2008
Growers planting transgenic
corn-on-corn should rotate traits to avoid yield penalties of up
to 20% from volunteer corn.
That’s according to Bruce Battles, Agronomy Marketing Manager
with Syngenta Seeds, Inc.,
speaking on Friday at the 2008 Commodity Classic in Nashville,
Tennessee. His remarks were part of a Learning Center session on
protecting yield potential in continuous corn.
“Transgenic hybrids give you an option – other than cultivation
– for controlling volunteer corn in continuous cropping systems,
but that’s only if you rotate your herbicide-tolerant traits,”
said Battles. “If you’re planting glyphosate-tolerant corn after
glyphosate-tolerant corn, for example, you’re eliminating any
postemergence spray option.” The same goes for planting
LibertyLink® corn after LibertyLink corn.
While not as ugly as volunteer corn in a sea of soybeans,
volunteers in continuous corn can cause significant yield loss.
New evidence suggests that volunteers also may reduce rootworm
protection from Bt hybrids by providing an alternate, non-toxic
food source, said Battles.
In a 2006 University of Illinois weed control study at Urbana
and DeKalb, volunteer corn reduced yield of glyphosate-tolerant
corn by 42% and yield of LibertyLink corn by 60%.
“These plots were uniformly seeded with volunteer corn and are
more reflective of extreme field situations where you might have
had severe lodging/ear loss or the wrong combine setting,” said
Battles.
To simulate infestations resulting from lodged corn, agronomists
with Syngenta Agronomy Research seeded test plots in 2007 with
either kernels or ears, at different densities, left over from
the previous year. Yield losses from the heaviest density of
ears (four ears per five row feet) was as high as 20%, whereas
yield losses from individual volunteer plants at the same
density was only 6%.
“The take-home message here is if you don’t plan ahead,
volunteer corn can back you into a corner,” said Battles.
For 2008 planting, Syngenta trait offerings include double and
triple stacks that combine the Agrisure® RW trait for rootworm
control with traits for glyphosate tolerance and/or resistance
to LIBERTY® (glufosinate) herbicide. New for 2008 is the
Agrisure 3000GT quad stack, which combines rootworm and corn
borer protection with resistance to both glyphosate and
glufosinate herbicides.
“If you’re following a conventional hybrid, then you can use
your choice of Agrisure GT/RW traits or Agrisure CB/LL/RW traits
to expand your weed control options,” explained Battles. “If
you’re following a herbicide-tolerant hybrid, then you need to
rotate your traits or go with a stack like the new Agrisure
3000GT quad stack.”
Battles said planting back to soybeans every third or fourth
year is an effective way to break the weed and disease cycles of
continuous corn while allowing for clean-up of
glyphosate-tolerant and glufosinate-tolerant volunteers with
alternate chemistries like Fusion® and Fusilade® herbicides.
Syngenta is a world-leading agribusiness committed to
sustainable agriculture through innovative research and
technology. The company is a leader in crop protection, and
ranks third in the high-value commercial seeds market. Sales in
2007 were approximately $9.2 billion. Syngenta employs over
21,000 people in more than 90 countries. Syngenta is listed on
the Swiss stock exchange (SYNN) and in New York (SYT). Further
information is available at www.syngenta.com.
Agrisure®, Fusilade® and Fusion® are trademarks of a Syngenta
Group Company.
LIBERTY® and LibertyLink® are trademarks of Bayer CropScience |
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