This proposal aims to better understand the herbicide resistant waterhemp and to look ahead at non-chemical weed
control options for Missouri soybean producers

The objectives we would like to address:
1. Test the 6-way resistant waterhemp population to confirm or negate its resistance to the seventh type of herbicide,
which has not been applied.
2. Demonstrate waterhemp control when multiple tactics are used.
3. Investigate what cereal rye seeding rate is necessary to reduce waterhemp emergence.
4. Study the effectiveness of the Case IH integrated weed seed destructor by taking the implement to Missouri soybean
farms for testing

Conducting greenhouse screens to confirm or negate what was observed in the field. And if needed, carry out field trials to further confirm or negate. Results will be presented to Missouri producers and technical audiences to emphasize the need to think beyond current chemical control options.

Keep trial going in the same location to better understand the long-­term benefits or costs associated with the added non-chemical control aspects. Additionally, within the next couple of years, this trial site should be an effective visual demonstration at field days for Missouri farmers to look at the impact of combining non­-chemical control options and for further study of all of the potential advantages and disadvantages of narrow windrow burning.

Updated April 27, 2021:
This project aims to better understand the herbicide resistant waterhemp and to look ahead at non-chemical weed control options for Missouri soybean producers. The objectives include:
1. Test 6-way resistant waterhemp population to confirm or negate resistance to the 7th type of herbicide, which has not been applied.
2. Demonstrate waterhemp control when multiple tactics are used.
3. Investigate what cereal rye seeding rate is necessary to reduce waterhemp emergence.
4. Study the effectiveness of the Case IH integrated weed seed destructor by taking the implement to Missouri soybean farms for testing.

The Seed Terminator is a weed seed destruction implement that can be installed in current commercial combines and has become one of the common methods of at-harvest resistant weed seed destruction in Australia. The Seed Terminator was installed on a Case IH 8250 combine and the Mizzou weed science program valuated the efficacy of this implement in 4 soybean fields in central Missouri in 2019.

In the first season of research with the Seed Terminator, our initial impressions and observations are that a high percentage of waterhemp seed that enter the combine are successfully ground up and eliminated by this implement.
Currently, our group is working to quantify and determine the viability of weed seed that passed through the Seed Terminator for more than 500 samples collected from the 4 soybean fields. An initial analysis of some of the combine engineering data suggests that engine load and fuel consumption of the combine will likely be slightly higher when the Seed Terminator is engaged compared to when it is not. Thus far the data is inconclusive as to the effects of this implement on the speed of harvest.

All research will be repeated in 2020 and demonstrations of some of this equipment will occur at the 2020 Pest
Management Field Day at the Bradford Research Center this summer.

Research results will provide Missouri soybean producers with timely knowledge on non­chemical weed control options as more herbicides are rendered ineffective. Conducting research now on alternative control measures so that non-chemical weed control options will have been tested and will be ready when they are needed. Postponing non-chemical weed control research until all available chemical control options have been exhausted would be a mistake and would leave producers with a lack of weed control options and even more serious herbicide-resistance issues than producers currently face.