With input costs rising and insect pressure varying from year to year, it's not always clear whether insecticidal seed treatments or foliar sprays actually deliver a return. We know that insecticides can prevent yield loss, but questions remain about which pests are most detrimental, the extent of damage they cause, and which control method is most cost-effective. This Illinois Soybean Association (ISA) checkoff-funded research, led by Dr. Nick Seiter, Assistant Professor & Field Crops Entomologist at the University of Illinois Urbana-Champaign, is designed to answer these questions to determine if insecticides really pay off. To help find out, we need farmer participation!  

Last year, ISA partnered with farmers through the On-Farm Trial Network to take this research beyond university plots. For the 2026 growing season, we're again seeking Illinois farmers to participate, with the option to focus on either foliar sprays or seed treatments in soybeans. The foliar insecticide study will involve two treatments:  

• Foliar insecticide application at R3 or R5 (farmer's choice of timing)
• Untreated control  

For the seed treatment study, we are seeking farmers who actively use cover crops, since higher-residue systems can harbor additional pests. This research will help us better understand how effective early-season control methods really are. This insecticide seed treatment study has two variations to choose from, each with two treatments: 

• Option 1 
  • Seed with insecticide 
  • Naked seed (no seed treatment) 

• Option 2
  • Seed with insecticide and fungicide
  • Seed with fungicide only 

With options in both foliar and seed treatment studies, farmers can choose the approach that works best for their operation. For data collection purposes, each study must meet the following requirements: 

• Minimum of 40 acres 

• Four replications of each treatment  

• Same soybean variety across all treatments 

• Harvest with a calibrated yield monitor 

The Seiter lab will handle soil sampling, insect counts, and injury assessments throughout the season. Please see the linked protocols for full details on requirements and responsibilities: foliar insecticide protocol and insecticide seed treatment protocol. 

If you are interested in collaborating with Dr. Seiter to implement one or both studies, please fill out the ISA On-Farm Trial Network interest form. For questions, contact Dr. Seiter directly at nseiter@illinois.edu or 812-593-4317. He can answer any questions you may have about implementing this research on your farm.  

Qualified farmers participating in ISA's On-Farm Trial Network may be eligible for stipend payments. Eligibility requirements and payment amounts will vary based on specific program guidelines. The On-Farm Trial Network is funded by the Illinois Soybean checkoff program.