Using Adjuvants in Your Pesticide Program

Katelyn Miller, Field Crops and Forage Specialist
Southwest New York Dairy, Livestock and Field Crops Program

April 10, 2023
Using Adjuvants in Your Pesticide Program

An adjuvant is a substance added to a pesticide or spray mixture with a specific function. Different functions include improving mixing, application, and pesticide performance. Formulations can be customized for specific needs and local conditions, making it important to understand their characteristics.  As planting season approaches, it's a great time to review how adjuvants can improve pesticide efficacy.  Let's start by reviewing the various types of adjuvants you can use in a pesticide mix. 

Surfactants help spread pesticide spray droplets evenly. They are also referred to as wetting agents or spreaders because they create a wet leaf surface by decreasing water surface tension. Be careful not to use too much surfactant, as it can cause excessive runoff and reduce pest control.

Stickers increase the adhesion of solid particles to a target surface. They can help reduce evaporation and the amount of pesticide that washes off during rain. Many adjuvants are formulated as spreader-stickers which help spread the pesticide over the leaf surface and adhere to it.

Extenders keep pesticides on the target surface which slows down evaporation and prevents the sun from breaking it down.  

Plant Penetrants enhances the penetration of some pesticides into plants.

Compatibility Agents are commonly used to help products mix. They help to reduce clumping, fix uneven distribution, and help to reduce the plugging up of the pump.

Buffers and Acidifiers acidify and stabilize the water in the spray tank. Most pesticide mixes are stable between a pH of 5.5 to 7.0, so the goal is to keep it within this target for the best efficacy.

Drift Control Additives improve placement target by increasing average droplet size.

Thickeners slow the evaporation of pesticides by increasing the thickness (viscosity) of the mix.  

Defoaming Agents work to reduce foam created by some pesticide formulation agitation.

Foaming Agents can be added to a spray mix to do the opposite of defoaming agents. Certain formulations work better with foam as it can help reduce spray drift. Usually, foaming agents are used in difficult to reach areas like septic pipes, under stoops, or for termite control.

Now that we've reviewed the types of adjuvants, it's time to take into account some important considerations for selecting one. Keep in mind some of the considerations below with the goals of your farm's pesticide program.

  1. A single adjuvant can't do everything. Compatible adjuvants can often can be combined to perform multiple functions at the same time.
  2. Know when and when not to use an adjuvant. Some formulations already use an adjuvant, so double check before adding one to the mix.
  3. ALWAYS read the label. The "Directions for Use" section will provide mixing instructions, and if any adjuvants are recommended.
  4. Look for recommendations, suggestions or implied use like the examples shown below.
  5. Make sure your adjuvant of choice has been thoroughly tested and marked for pesticide use. If you are unsure of its efficacy, test the product on a small area first.
  • "spray coverage should be uniform and complete"
  • "thorough spray coverage is important"
  • "spray mix combinations must be compatible"
  • "coverage should be maximized"

There are many options for using adjuvants, so always read the label for instructions and learn which ones can help suite your current pesticide program. If you want more information on adjuvants, refer to the DEC CORE Book, which you can purchase here https://www.cornellstore.com/books/cornell-cooperative-ext-pmep-manuals?page=1. You can also visit  https://extension.psu.edu/spray-adjuvants.




Field Crops

Field Crops

Dairy

Dairy

Business

Business

Livestock

Livestock

Grains

Grains

Upcoming Events

Driving Efficiency in Dairy & Exploring the Irish Experience

September 29, 2025
Rock Stream, NY

This workshop series will feature in-depth presentation and discussion led by Dr. Padraig French who is the Head of Livestock Systems and the Dairy Enterprise Leader at Teagasc (the Irish version of USDA). Dr. French will focus on the critical success factors for Irish dairy, which include pasture utilization, labor efficiency and managing for seasonal calving. The discussion will focus on ways that U.S. dairy farmers can use some of the Irish dairy techniques to become more profitable with grass farming.

View Driving Efficiency in Dairy & Exploring the Irish Experience Details

Silvopasture on a Shoestring

October 7, 2025
Franklinville, NY

Join Joshua Greene, Director of Education at Trees For Graziers, Jonathan Bates, Statewide Agroforestry Educator, and Lynn Bliven, owner of Wild Geese Farm for a full day training event that will include classroom and hands-on sessions. The focus will be on DIY silvopasture projects on small grazing farms. We will address the practical considerations of tree establishment, protection, and maintenance while learning how silvopasture can help address your farm's resource concerns and enhance livestock grazing.

View Silvopasture on a Shoestring Details

Crops, Cows & Critters - Southwest New York Dairy, Livestock & Field Crops Newsletter Sponsorship

December 19, 2025

Our two forms of publications feature research-based and timely information from our four specialists, listed to the right, along with local event notifications and Cornell University outreach. This information is provided to participants who range from dairy, livestock, and field crops producers to agricultural suppliers and consultants.

Weekly Email Update: Shared with 625+ households who have signed up with our program.
Monthly Paper Mailer: To reach our stakeholders and farmers who lack internet access, we send out a monthly mailer where your company's logo and contact information would be featured with a mailing list of 330+ households.

If you sponsor our weekly and monthly publications you reach approximately 955 households.

Visit our website to view our newsletters!

View Crops, Cows & Critters - Southwest New York Dairy, Livestock & Field Crops Newsletter Sponsorship Details

Announcements

No announcements at this time.

NEWSLETTER   |   CURRENT PROJECTS   |   IMPACT IN NY   |   SPONSORSHIP  |  RESOURCES   |   SITE MAP