Resistance is not futile
As you plan for next season’s weed control, think preemergence
In my April column, I visited about the use of preemerege herbicides and their need in assisting producers’ battle against herbicide resistance. Over the past few months, I have had several calls claiming residual herbicides had no value on growers’ farms, while other growers stated that residual herbicides were the best thing since sliced bread. I learned through visiting with a particular customer that he applied the residual herbicide behind the press wheel and started clean. However, the first rain on the field didn’t come until nearly four weeks after application. The activating rain was too late. It is likely the herbicide was already degraded by the first rain and the weeds were already emerging with the crops. Unfortunately, that situation was all too common this year.
Another all-too-common issue for 2012 was to plant first and then later attempt to clean up the field. Once the crop is planted, the options for controlling weeds such as giant ragweed, marestail and waterhemp are limited. Tillage is a viable herbicide option before the crop is in the ground.
I am talking about the failures of weed control this year to remind you that there are no silver bullets. As much as I would like to inform you that using glyphosate the same way you always have used will deliver the same results, that just isn’t the case.
As we move into the planning process for the next growing season, let’s prepare for success. Residual herbicides must continue to be a foundation for any cropping system. Even though we need moisture to activate the herbicide, it is still our best option to controlling weeds. Our best chance to control tough weeds is to never allow them out of the ground. The use of residual herbicides adds another management step to our programs, but we must be willing to manage the weeds or they will manage us.
If you planted LibertyLink soybean this year, I hope enough Liberty was available to cover your acres. The shortages of Liberty were global, making it a very stressful year across all the crop growing areas in the United States. As we progress into preparing for next year, go ahead and book your Liberty for the next season with your local MFA. I often get the question of how much Liberty a particular grower will need, and my general response is two full-labeled-rate applications worth. Two applications not only allow you to feel comfortable about the technology, it also allows our stores to plan for the next year’s Liberty supply. Even though Liberty has been very effective, I also recommend the use of residual herbicides at the full-labeled rate. Application of the residual herbicide will not only reduce the amount of pressure you are putting on Liberty, but add another mode of action to the mix.
In May, MFA gained a staff agronomist, Kellar Nelson, who has been tasked with the LibertyLink project. She graduated from the University of Missouri with a Master’s in Plant and Soil Science. This past year, MFA planted ten LibertyLink soybean variety trials across the state. Nelson visited these trials bi-weekly from planting to harvest to evaluate variety placement throughout the state.
Contact your local MFA for Nelson’s and other final variety yield reports or for more information on MorCorn, MorSoy Xtra, or MorSoy LibertyLink crops.
Dr. Jason Weirich is director of agronomy for MFA Incorporated.