The importance of proper tank mixing

When completed correctly, tank mixing pesticides can be a cost- and time-saving practice for superintendents. However, fungicides should always be evaluated for compatibility prior to tank mixing to ensure combining them is not prohibited on any of the respective labels, and to determine whether the combination is compatible.

The best way to evaluate compatibility is to conduct a jar test:
Diagram A:

  • In a 1-quart jar, add 1 pint of carrier (water or fluid fertilizer) and 1 teaspoon of chemical per ounce of carrier being used in the field according to the WALES method (described below) 
  • In a second 1-quart jar, add 1 pint of carrier, the chemical and a compatibility agent
  • The chemical should be added into each jar in proportion to the recommended rates for use in the field

 Diagram B:

  • Close both jars and shake them vigorously for 30 seconds each
  • Let the jars stand for 30 minutes before checking results
  • If the mixture in the first jar (without the compatibility agent) stays mixed, use that combination in the spray tank
  • If the mixture in the second jar (with the compatibility agent) is mixed, but the other jar is not, add the compatibility agent into the spray tank

Diagram C:

  • Should either mixture separate after five minutes, but mix readily after shaking, the mixtures can be used in the spray tank as long as good agitation is maintained
  • If a separate oily layer, large oil globules, clumps of solids or sludge form in the bottom of the jar containing the compatibility agent, the mixture should not be used


The WALES method
Some product labels specify which products can and cannot be tank mixed, but there may be situations where you want to tank mix products that are not listed in either category. In these instances, follow the WALES method for the recommended order of operations for tank mixing. Before beginning, remember that water should always go into the spray tank before anything else (fill the tank at least one quarter of the way full and start agitation before adding products). Also remember that you are required to meet the personal protective equipment and clothing requirements of all the product labels.

W – Add products packaged in Water Soluble Pouches, Wettable Powders (WP) or Water Dispersible Granules (WDG) into clean water before any other material is added to the tank.
A – Agitate thoroughly to ensure dispersion and/or dissolution of solids. Maintain agitation during mixing and spraying. Allow each product to mix thoroughly before adding new materials.
L – Add Liquid Flowables next. These are usually called Suspension Concentrates (SC) or Suspo-emulsions (SE).
E – Next, add Emulsifiable Concentrates (EC) or Micro Emulsifiable Concentrates (MEC).
S – Lastly, add Solution (SN /SL) type products. Then fill the rest of the tank with water and continue to agitate until completion of spray operation.

Mixing these components in an order different than the one specified above may result in separation within the tank. To learn more, view this brochure about tank-mixing tips and procedures. 

Always consult the product label for complete use and application information.

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

© 2024 Syngenta. Important: Always read and follow label instructions. Some products may not be registered for sale or use in all states or counties and/or may have state-specific use requirements. Please check with your local extension service to ensure registration and proper use. The trademarks or service marks displayed or otherwise used herein are the property of a Syngenta Group Company. All other trademarks are the property of their respective third-party owners.

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