Iowa Farmer Today
01-13-07
Volunteer corn significant challenge
By Tim Hoskins, Iowa Farmer Today
While traditional weeds will continue to be the main problem most Iowa farmers
will face, certain areas will have significant volunteer corn issues in 2007.
“There is an increased likelihood for more volunteer corn in 2007,” says Mike
Owen, Iowa State University Extension weed specialist.
The reason is due to environmental conditions, such as wind damage in 2006.
Volunteer corn will likely be present in soybeans and corn fields.
He says volunteer corn has always been a tough weed to control but use of
biotech hybrids might make it even tougher.
Field history should be on the top of a farmer’s mind when dealing with volunteer
corn.
In soybean fields, which are most likely
glyphosate resistant, Owen says the volunteer corn could be glyphosate resistant
as well if resistant corn was grown in the same field the previous year.
Another reason volunteer corn may be Roundup Ready is due to pollen drift from
neighboring glyphosate-resistant corn fields.
“Pollen does not understand field boundaries. It goes where it wants to go,”
Owen notes.
He says if the volunteer corn is Roundup Ready, it is best to mix a postemergence grass herbicide with the Roundup application. However, if it isn’t
glyphosate-resistant volunteer corn, a glyphosate application should take care of
it.
If the glyphosate application does not care of it, a post-emergence grass
herbicide application might be needed, which would require another field pass.
Controlling volunteer corn in a planted corn field might require more
management.
Owen says volunteer corn has always been hard to control in corn fields.
Field history could be another factor to solve the problem of volunteer corn in
corn.
He says one solution for Roundup Ready volunteer corn, especially in corn fields,
is to plant Liberty Link hybrids.
Using a Liberty Link system also would help control any selection pressure for
glyphosate-resistant weeds in a field, Owen says.
However, he says farmers need to note the field history and what was grown in
fields next to them the past year if they plan to switch to a Liberty Link hybrid to
control Roundup Ready volunteer corn.
While using the Liberty Link system could effectively control Roundup Ready
volunteer corn, it might not be effective in controlling volunteer corn from
Hereclux/Roundup Ready hybrids.
That is because the Liberty Link gene is a marker for the Herelcux trait.
Therefore, switching to a Liberty Link corn hybrid might not solve the problem.
He says this drives home the point the glyphosate-resistant system is not an
easy system.
“People think this system is simple. It is not,” Owen says.