Treating corn seed has long been tradition, but not treating soybeans. Corn seed has been treated with a fungicide for decades because hybrid seed production was commercial, and seed companies wanted to get the best performance out of each seed planted.

But soybean seed treatments are a more recent advancement, especially since farmers stopped bin-running soybeans. Even on our family farm, we did not treat soybeans until I came on the scene more than a decade ago and wanted to adopt the best production practices. For year’s farmers either bought soybean seed or bin-run seed they produced on their own farm—back then treating seed was something they had to do themselves. Either they used planter box treatments or bought some equipment to treat on-farm, but it was messy and inaccurate. I was the one who dealt with the mess, and I always wondered about accuracy and effectiveness.

Today that has all changed, and farmers rarely treat their own seed. Soybeans are either treated at a commercial seed plant, or more likely at a local seed dealership that has the right equipment and training to effectively treat seed. I also have given up on treating seed and rely on a dealer to do it. I now have fewer headaches and greater confidence in the outcome.

Still, some farmers still ask if seed treatment is important. Farmer surveys reveal that 80 percent or more of the commercial soybean seed is being treated today. The trend to treat soybean seed has been increasing for a decade now as seed has gotten more expensive, farmers reduce population rates and they plant earlier and in harsher environments. Remember a few decades ago soybeans probably were all planted around May 15, when the soil was warmer and drier, and the beans germinated and emerged quickly.

Not long ago, farmers only treated soybean seed if they were going to seed early or do no-till. No one saw any value in treating soybeans if they were going to seed using conventional tillage or seed in a normal time frame. Many farmers now recognize that seed treatments have as much value for soybeans as corn—and maybe even more since soybeans seem more vulnerable to seedling diseases than corn.

And I was surprised to learn at a recent double-crop roundtable held in St. Louis that seed treatments are increasingly being used when soybeans are planted after wheat in late June or early July. There is probably no harsher environment than soils that are very warm and have pathogens that are very active.

Today’s seed treatments can be a mixture of complex cocktails of products including several fungicides to control a broader range of pathogens, insecticides, nematicides, biological inoculants and additives to improve flow in today’s central fill planters. With so many products available and being applied at very low rates per seed, it takes good equipment and a skilled applicator to treat seed today.

Not all products are compatible and they can impact product efficacy or damage seed. So, seed treatment manufacturers and seed companies do their own testing to know what chemistries are compatible and which could have a negative effect on the germination of the seed or impact seed flow/plantability. If you mix your own cocktail of products and treat your own seed, you will not have the benefit of that knowledge and experience.

Is all of your soybean seed treated today? Who does it and what products are being applied—or do you leave that decision up to your seed dealer?

Dr. Daniel Davidson, agronomist, posts blogs on agronomy-related topics. Contact him at

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About the Author: Dan Davidson

Soybean agronomist Daniel Davidson, Ph.D., posts blogs on topics related to soybean agronomy. Feel free to contact him at or ring him at 402-649-5919.