What’s the difference - biologicals and biostimulants?

What’s the difference - biologicals and biostimulants?
Jul 17, 2025
By Jean-Paul McDonald
Assistant Editor, North American Content, Farms.com

What Farmers Should Know About Biologicals

Illinois farmers often ask if biological products really work. Fred Below and Connor Sible from the University of Illinois Urbana-Champaign hear this question frequently. They believe biologicals and biostimulants are useful but need clear definitions and proper regulations. 

Biologicals are living microorganisms added to soil, seeds, or plants to support growth.  

Biostimulants are natural substances like plant extracts or organic acids used for the same purpose. These products help improve crop yield, soil health, and reduce stress on plants. 

The confusion arises because farmers, companies, and scientists use different names for the same products. Also, regulations for these products are unclear or missing.  

Sible, and researcher Juliann Seebauer recently published some findings to help clarify the issue for farmers and lawmakers. 

Biologicals started with soybean inoculants but later expanded to specialty crops. As their use grew in corn and soybean farming, hundreds of products flooded the market with various claims. However, many of these claims lack strong research support. 

Currently, only microbial inoculants are regulated under U.S. federal law. Most products are overseen by states, but each state has its own rules, which contributes to the confusion. Some products are labeled differently depending on the state. 

The researchers recommend separate federal rules for biologicals and biostimulants to ensure safety and fair marketing. Living microorganisms may pose different risks compared to non-living products, so both should not be grouped under the same regulations. 

The researches say the goal is not to limit the industry but to make sure farmers benefit from safe, effective products. “For this market and how fast it's growing, we need all of the perspectives — academics, industry, and farmers — to come together on these products,” said Below. 

Their study aims to create a common language and regulatory path that supports farmers and the agriculture industry. 

Biostimulant or biological? The complexity of defining, categorizing, and regulating microbial inoculants,” can be found here:  

Photo Credit: University of Illinois Urbana-Champaign 

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