Herbicide resistant and difficult to control weeds cause yield loss and significant management costs to soybean farmers. We will: 1) establish demonstration plots to provide today’s best options for weed management; 2) assess herbicide treatments on glyphosate resistant waterhemp using combinations of herbicide chemistries and 3) Establish simulated drift on non dicamba soybeans and determine effects on yield.
The information gained on herbicide resistance, and Xtend soybean project has been, and will continued to be, presented through outreach and education materials to soybean farmers through information at applicator training, Soy 100, field days, and written materials.

1. Establish demonstration plots in three areas of SD that highlight today’s best herbicide options and application
timings for resistant weed control in soybean.
2. Assess alternative herbicide treatments on glyphosate resistant waterhemp with more modes of Action.
3. Establish simulated drift on non-dicamba soybeans and determine effects on yield.

Updated October 31, 2022:
First Quarter Report on Controlling Weeds in Soybeans
The year started out fine all plots were planted on time and were off to a good start. The Southeast farm was very short of moisture and limited soybean production. At this point all soybeans have been harvested and weed control data and yields are being analyzed. This data will be available for the winter meeting season again and will be presented at winter meetings.

Updated January 30, 2023:
I would like to announce that the WEED Project will have a new leader starting March 5. Eric Jones is a native of Iowa and did his BS and MS degrees at Iowa State he did his PHD at North Carolina State. In the meantime, most of you know I have been working part time since July. The project is coming along fine all data have been analyzed. The results have been published in the Weed control data book for 2022. The Southeast research report and the Northeast research with the data from each of their locations. I have used this data in all the talks I have given so far this year. Examples like the row crop meeting at Watertown with over 250 people in attendance and Commercial applicator meeting in Mitchel with 150 people in attendance. I will post all the data in the reports as I get time to put them up.

Updated April 24, 2023:
The report listed below in the uploads Is the studies funded by the Soybean Counsel. The January report showed some of the early meetings that the data was presented at. Since that time the data was used at more commercial applicator meetings and Crop Consultants and other weed meetings. It has been fun working with the Soybean Counsel directly for the last ten years and indirectly for close to thirty years before that I plan to stay involved with the ag industry in my retirement. Eric will be leading the project moving forward and will do a fine job.

View uploaded report

The first objective is to continue herbicide demonstration plots at three eastern South Dakota experiment station farms. These studies are needed to allow producers to observe performance of products in their local area and under local environmental conditions. These studies allow informed decisions about products without company bias and help demonstrate how different timings, tank-mix combinations, and sequential applications enhance or deter herbicidal weed control efficacy.
A series of herbicide program demonstration plots including herbicide (glyphosate) resistance options in soybeans will be established at three locations; Southeast SD Research Farm (Beresford), Northeast SD Research Farm (South Shore) and the SDSU Volga Research Farm. The primary objective of this portion of the project is to increase grower knowledge of herbicide resistance in soybean weed control programs (primarily common waterhemp and kochia) and help growers to fine-tune their weed management strategies. The strategies will include treatments of preemergence, pre-post combinations, post emergence, and new technology herbicide options such as Liberty, Xtend, Enlist and Allite with “GT27 soybeans” .

The demonstration plots will be utilized for grower and professional agronomist tours and training events. Data taken from the plots will include weed efficacy, crop injury ratings, and yield. Cost of treatment will also be calculated. Results will be printed in the annual SDSU Extension WEED Project Data book and will also be used in updating the weed control section of the SDSU Soybean Pest Management Guide. Pictures of the plots and plot data will be used at winter meetings around the state. Examples of meetings that data will be used at include Commercial Applicator Training, Private Applicator Training, Row Crop Clinics, IPM Consultant Training.

The second objective is to establish plots with different mixtures of glyphosate and glufosinate to make both the most effective as possible. In preliminary work it appears that there may be some antagonism if the two are sprayed together. The studies will look at different rates of mixtures and also different timing of the use of these products. The study will be done at two sites. One at the Volga research farm with heavy glyphosate resistant waterhemp and lambsquarter. The second at the NE research farm where there is heavy yellow foxtail along with pigweed, and ragweed.

The plots will be utilized for grower and professional agronomist tours and training events. Data taken from the plots will include weed efficacy, crop injury ratings, and yield. Cost of treatment will also be calculated. Results will be printed in the annual SDSU Extension WEED Project Data book and will also be used in updating the weed control section of the SDSU Soybean Pest Guide. Pictures of the plots and plot data will be used at winter meetings around the state. Examples of meetings that data will be used at include Commercial Applicator Training, Private Applicator Training, Row Crop Clinics, and IPM Consultant Training.

Simulated drift on non-dicamba soybeans has mainly been done on soybeans at early growth stages. This study would be looking at application at the last labelled date for dicamba application (late June). This experiment would help to determine in South Dakota conditions if visual injury symptoms and yield are different at these later dates with the new dicamba products. Also, the treatments will have a PPO herbicide applied one week before, same time and one week after application which causes burn to soybean to determine if this will result in greater injury and yield loss. Injury ratings and pictures would be taken weekly until symptoms dissipate. The drift trial will be conducted at the Volga research farm where the plot can be watched closer during the growing season.