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Contacts: Julie Christensen, U of M Extension, (612) 626-4077, reuve007@umn.edu;
Andrea Johnson, Minnesota Farm Guide, (320) 289-2256, andreaj@mchsi.com
ST. PAUL, Minn. (3/24/2008) — Not all the facts are in yet, but adding wheat to the southern and central Minnesota crop rotation may decrease lodging in corn.
Several southern Minnesota producers commented recently on this phenomenon during the University of Minnesota Extension's "Southern Wheat Tour" workshops.
"Inclusion of wheat in their rotation had made a dramatic difference last summer in the amount of lodging in their corn in fields that were on a three-year rotation rather than a corn-soybean rotation," said Jochum Wiersma, University of Minnesota Extension small grain specialist.
Wiersma thinks adding wheat to the rotation may affect the two-year life cycle of some northern corn rootworm.
Rootworms typically have a one-year life cycle, but some northern corn rootworms have adapted to the corn-soybean rotation. The eggs remain dormant in the soil for two years before hatching – an extended diapause.
Moving towards a corn/soybeans/wheat rotation may reduce extended diapause rootworm pressure.
"Hatch from corn rootworm eggs declines with exposure to successive winters, and there is no evidence yet of significant egg laying in either soybeans or small grains," Wiersma said.
"Even though beetles may be active in nearby crops or weeds, northern corn rootworms return to corn to lay their eggs."
The small grains specialist would like to see field experiments conducted to prove or disprove this hypothesis. He would also like to hear from producers who have anecdotal evidence of corn lodging or the lack of it following wheat production.
Comments for Wiersma can be left at AgBuzz.com, an Internet agriculture blog featuring University of Minnesota Extension and hosted by "Minnesota Farm Guide."
Wiersma's column is entitled, "Wheat and Northern Corn Root Worm."
Grab a cup of coffee and join the conversation at AgBuzz.com!
