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| Weed control critical to non-GMO planting |
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There are a number of reasons why a producer may go back to producing non-genetically modified organism (GMO) soybeans. The increase in acres planted to non-GMO will lead to more fields that have less than excellent weed controls since weeds are more difficult to control with conventional soybean herbicides. We all tend to forget that we need to follow a system to control weeds in non-GMO soybeans.
According to Mark Loux, Ohio State University Extension specialist, if you follow a system you should be able to adequately control weeds. First, start with a weed-free field at planting either through tillage or herbicide burndown. Be sure to include a broad spectrum residual herbicide in the pre-plant application. Most importantly, apply post emergent herbicides to small weeds and last, make a second post emergent application for late emerging weeds or to complete control of grant ragweed. In fields with relatively low weed pressure, Loux suggests the pre-plant residual herbicide should provide enough control that only one post treatment spray would be needed.
You can find more detail online at: http://agcrops.osu.edu/weeds
Dr. Loux points out that our guidelines emphasize the use of Flexstar and Cobra/Phoenix because many fields contain ALS resistant populations. You can use Classic or FirstRate as the primary post treatment but only where you are sure you do not have an ALS resistant weed population. Be aware that the use of PPO inhibitors in pre-emergent mixtures and post application increases selection pressure and weed resistance for these herbicides. If weeds in a field were to develop resistance to glyphosates, ALS and PPO - what a mess.”
Loux suggests you use 2-4D if you are using a chemical burndown product.
It is possible to supplement the pre emergent tank mix with additional metribuzin, such as Canopy DF plus metribuzin, so that the PPO inhibitor is de-emphasized. Where the weed populations are not ALS resistant, post Flexstar with Classic or FirstRate will provide two modes of action. |
| 3/25/2009 |
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