Research HighlightsSoybean Aphid Control Makes Economic Sense for Farmers
In this article, you’ll find details on:
- This research project tests 11 pesticides for soybean aphid control and soybean yield impact in central Minnesota.
- The trials are conducted by an independent contract company, which provides unbiased, third-party data that farmers can use now.
- Results show what products worked best and compared them to no control, which could lead to large yield losses for farmers.
By Carol Brown
Farmers must know what inputs they need to combat weed and pest issues in their crop fields. Many rely on their local retail agronomist to help find the right products for their fields and management system. Companies test and adjust their products to be most effective for farmer productivity.
Andrew Lueck owns Next Gen Ag, an independent contract research company he started in 2017, which helps private companies test their products in replicated small plot research trials. Based in Renville, Minnesota, he conducts trials on weed and pest control products, biologicals and nutrients, and crop varieties, depending on independent protocol requirements. He has been working with the Minnesota Soybean Research and Promotion Council (MSRPC) for eight years.
“A portion of my business is through grant funding, and the Soybean Council has supported around 50 trials with me over the years,” says Lueck. “Having grown up on a farm and knowing the importance of return-on-investment, I understand that farmers need third-party, unbiased, replicated data. The Minnesota soybean growers tend to agree as they continue to support these efforts. This is one of the reasons I began my business, supporting research for the next generation of agriculturalists.”
In 2023, MSRPC funded three grants with Lueck: herbicide comparisons for giant ragweed and waterhemp control, a trial of variable rate tank mixes for waterhemp control, and a comparison of pesticides for soybean aphid control and yield impact.
Controlling Soybean Aphids
In the aphid trials, Lueck tested 11 products from six companies. Untreated soybeans were grown on all plots to mitigate the impact of seed treatment on aphid populations, and an untreated check plot with no aphid control was included. The products were applied on August 3, after he and his team had counted an average of 168 aphids per plant. Lueck uses an economic threshold of 150 aphids per plant, despite the 250-aphid economic threshold recommendation. All products included the adjuvant Masterlock applied at 6.4 fl oz/acre.
His team counted aphids three times: 1 day before application, then 6 and 14 days after applications. On October 3, they harvested six replicate plots for each treatment and collected yield data. Figure 1 lists the products and application rates, soybean yield, and aphids per plant based on aphid counts taken on August 9.
In Figure 1, the set of pesticides showing higher aphid counts includes pyrethroid (Group 3A) products, which soybean aphids have steadily become more resistant to over the last decade. The frequency of resistance to Group 3A insecticides was 49.5% in the evaluated populations.
Lueck recommends using multiple modes of action for controlling soybean aphids at the economic threshold to keep pesticide resistance from progressing. Most of the products that performed well were pre-mixes of multiple modes of action. According to his 2023 dataset, soybean aphid economic impact can be a yield loss of 3.5 to 7.7 bushels per acre. This corresponds to $45 to $100 per acre, based on $13 per bushel soybeans, depending on Group 3A population resistance and no treatment, respectively.
“We computed a negative correlation between soybean yield and aphid population, and concluded that 78% of the soybean yield loss is tied to aphid population increase,” Lueck says. “The fields had drought stress that increased plant susceptibility, large aphid populations and excellent response to treatment. This is one of those studies that makes me proud when it turns out as planned despite the randomness of environmental impact.”
Good Relationships Help with Impactful Data
Lueck strives to produce relevant, third-party data for soybean growers. The companies he works with supply the products they want tested, and MSRPC funds the labor and supplies. He views it as a win for all involved: the industry partners receive visibility, MSRPC gets non-biased data and product comparisons, and he enjoys conducting the trials.
“I feel I’m giving the MSRPC the best bang for their buck by providing data they can use to make decisions in the following year,” he comments. “I’m testing products head-to-head that are already on the market, not from products still in development. I try to show return-on-investment data that farmers can use in their decision-making. The data we generate are great discussion pieces for farmers and their crop advisors. Like many situations in life, it’s about being open-minded to new information.”
For this coming crop year, Lueck intends to conduct the aphid research again along with six other projects including a white mold trial for the Minnesota Soybean Research and Promotion Council.
To read the full report, “2023 Soybean Aphid Control Product Impact on Yield,” visit the Next Gen Ag website and go to “Latest News.”
Published: May 13, 2024
The materials on SRIN were funded with checkoff dollars from United Soybean Board and the North Central Soybean Research Program. To find checkoff funded research related to this research highlight or to see other checkoff research projects, please visit the National Soybean Checkoff Research Database.
