Four Ways to Apply Biologicals

Seed treatment. Soil-applied. In-furrow. Foliar. With so many application options available for biological products, you may wonder what the best option is for your acres. We’re here to break down the benefits of these application methods to help you make an informed decision.  

Biological seed treatments

Biological seed treatments are typically blended with standard insecticide/fungicide seed treatments in crops like cotton, soybeans and corn. Depending on the product, active ingredients may include beneficial bacteria, fungi, amino acids and other microorganisms that promote plant growth, enhance nutrient uptake or protect against pests and diseases. Some biological seed treatments are applied directly to the seed, while planter box treatments, like Dash™ PBC or Dash™ PBS, can be mixed with the seed in the planter box. 

Benefits:
•    Can help stimulate microorganism activity in the root zone
•    Helps protect an emerging seedling from early-season stress
•    Promotes vigorous early-season growth for a strong start
•    Easy to implement, requiring little to no extra time, fuel or labor

Soil-applied biologicals

Some biologicals can be applied to the soil using traditional spray equipment or irrigation systems. These products typically work best when applied near the root zone, as the microorganisms in soil-applied biologicals form a symbiotic relationship with plant roots. Soil-applied biologicals can help break down crop residue, improve soil health and increase nutrient availability. Some soil-applied biologicals may not be compatible with other fertilizers and chemistries, so be sure to follow label instructions and use high-quality water sources when applying them.

Benefits:
•    Can cover many acres efficiently
•    Supports the breakdown of crop residue 
•    Can help increase the availability of tied-up soil nutrients
•    Does not typically require special application equipment

In-furrow biologicals

In-furrow biologicals are placed in the furrow at planting to help promote root growth, increase nutrient cycling or protect against early-season pests. A two-year replicated study by the University of Illinois, comparing in-furrow applications of phosphorus-solubilizing microorganisms in corn, found that combining biologicals with starter fertilizer increased yields significantly compared with either product applied alone.¹ In WinField United Answer Plots showing a positive response, Ascend2 plant growth regulator (PGR) can help improve corn yield potential by 7.5 bushel per acre in corn compared to starter fertilizer alone.²

Benefits:
•    Can help boost the benefits of a starter fertilizer
•    Facilitates healthy root growth for better water and nutrient uptake
•    Can support faster, more even crop emergence
•    Stimulates microorganism activity near the root zone to release soil-bound nutrients

Foliar biologicals

Foliar biological products are applied via a spray application to the crop canopy. Products like biological fungicides and insecticides can help protect crops from yield-limiting pests, while foliar plant growth regulators can help enhance vegetative growth and reproductive development. Foliar biological products also can help mitigate the effects of stress like heat and drought. Research has shown that foliar-applied PGRs can increase corn leaf area and net photosynthesis rate by up to 13%.³

Benefits:
•    Helps promote photosynthetic efficiency
•    Increases in-season stress tolerance
•    Works synergistically with foliar-applied nutrients to improve uptake
•    Some products may be applied with foliar nutrients and/or herbicides and fungicides

Biological products with the WinField^® United BioVerified™ Designation

With a better understanding of the different biological application methods, you can build a strategy that fits your production practices and agronomic needs. Using biologicals at critical development stages throughout the season can provide synergistic benefits. Research suggests the combined use of plant growth regulators in seed treatment and as a foliar application in corn boosts the physiological activity of plants by stimulating the photosynthetic process.³

The WinField^® United BioVerified™ Designation helps simplify biological recommendations, and the products below have been rated based on four key criteria: uniqueness, agronomics, operational compatibility and economic return.    

Biological seed treatments

•    Dash™ PBC: Corn planter box seed treatment that provides seed lubrication and microbial benefits for enhanced yield potential.
•    Dash™ PBS: Soybean planter box seed treatment that provides seed lubrication and microbial benefits for enhanced yield potential.
•    Ascend® ST3™ plant growth regulator (PGR): An auxin-dominant three-way PGR mixture that can promote root initiation and growth while helping mitigate early-season stress.
•    Heads Up®: Soybean seed treatment that can protect against pythium, white mold and SDS.
•    Vault® IP: Soybean seed treatment with a dual-strain biofungicide plus a nitrogen-fixing rhizobia strain.

In-furrow biologicals

•    Ascend2 plant growth regulator: Optimal ratios of auxin, cytokinin and gibberellic acid to help corn emerge faster, stronger and more evenly.
•    Zume®: Soil-applied enzymes that help enhance nutrient availability and uptake at the rootzone during early growth and development.

Foliar biologicals

•    Ascend® SL: Soluble liquid plant growth regulator mix that supports cell division, leaf expansion and root formation in corn, soybeans, cotton and other crops.
•    Source® DC: Microbiome activator that helps you get more nitrogen and phosphorus from your soil.
•    Voyagro® biostimulant fertilizer: Helps mitigate drought stress to corn, soybeans, cotton, wheat and other crops. 
•    YieldON® biostimulant: Increases row crop productivity by supporting healthy plant growth and improving sugar and nutrient transport.

Consult with your WinField United retailer for more information about how these products can help support your yield goals this season.

<sub>¹ Sible C and Below F. Role of Biologicals in Enhancing Nutrient Efficiency in Corn and Soybean. Crops and Soils Magazine. 2023. Doi: 10.1002/crso.20263 
² Based on over 60 trials across Answer Plot locations in 15 states from 2017 to 2021.
³ Luiz Piati G, Ferreira de Lima S, Lustosa Sobrinho R, et al. Biostimulants in Corn Cultivation as a Means to Alleviate the Impacts of Irregular Water Regimes Induced by Climate Change. Plants (Basel). 2023 Jul 7;12(13):2569. doi: 10.3390/plants12132569.

All photos are either the property of WinField United or used with permission.

© 2025 WinField United. Important: Before use always read and follow label instructions. Crop performance is dependent on several factors many of which are beyond the control of WinField United, including without limitation, soil type, pest pressures, agronomic practices and weather conditions. Growers are encouraged to consider data from multiple locations, over multiple years and to be mindful of how such agronomic conditions could impact results. Ascend2, BioVerified, Voyagro, and WinField are trademarks of WinField United. All other trademarks are the property of their respective owners.</sub>