Adjuvants Taking on a New Role Under Endangered Species Act

The Endangered Species Act is reshaping pesticide applications, with drift reduction and spray buffers becoming increasingly important for specialty crop growers.

American Fruit Grower and Western Fruit Grower spoke with Attune Ag, Loveland Products, and Wilbur-Ellis about how adjuvants can help growers navigate evolving regulations. Reponses have been edited for length and clarity.

1. How do you see the Endangered Species Act (ESA) changing the role of adjuvants in commercial fruit production?

Ed Quattlebaum, director of development, Attune Ag: “Adjuvants have been widely used in fruit production for many years, primarily to improve agricultural chemical delivery and performance. The ESA will likely increase their use as fruit growers add drift-reduction adjuvants (DRAs) to reduce required buffer zones.”

Connor Ferguson, senior branded technologies adjuvant portfolio manager, Wilbur-Ellis: “ESA requirements have brought greater attention to how adjuvants can mitigate spray drift and keep more droplets on target. DRAs have existed for decades, but their importance has grown because they can help growers comply with ESA requirements.”

Drew Butler, adjuvant portfolio manager, Loveland Products: “As EPA’s mitigation strategies evolve, adjuvants will likely play a greater role in helping growers optimize pesticide applications and meet label requirements.

“These new measures highlight the importance of selecting the right tank-mix partners. While no product can eliminate drift, certain technologies can reduce drift potential and support more precise applications.

2. Where do adjuvants fit into EPA’s system for reducing required spray-drift buffers?

Quattlebaum: “EPA has a system for herbicides that recognizes DRAs as a way to reduce buffer-zone requirements. EPA is proposing a similar system for fungicides and, ultimately, insecticides.”

Ferguson: “DRAs are just one part of reducing spray drift. Even the best adjuvant cannot compensate for poor application practices. Proper sprayer setup, favorable wind speed and direction, and using a DRA can all help more spray deposit where it is intended — a win for the environment and the grower.”

Butler: “Adjuvants are one of several tools available to applicators, alongside equipment selection, application timing, buffers, and conservation practices. Because adjuvants can directly influence spray characteristics that affect drift, they can play a meaningful role within a broader mitigation strategy. Recognizing proven technologies can give growers flexibility for meeting regulatory requirements, while maintaining effective crop protection programs.”

3. How significant would expanding drift-reduction adjuvant credit to fungicides and insecticides be for growers, as per EPA’s draft Fungicide Strategy?

Quattlebaum: “Fruit growers face mandatory buffer zones when applying agricultural chemicals that could harm endangered species. Using a DRA could allow them to reduce those buffers. The value of the crop protected will likely be higher than the cost of the DRA.”

Ferguson: “EPA recognition of DRA credit for fungicides would be a significant step. Most sprays applied deep into tree canopies target insects or disease, not weeds. Buffer-zone reductions would be important, and the right product could help fruit growers achieve multiple goals while complying with ESA regulations.”

Butler: “The significance will vary by operation. For those near sensitive areas, neighboring properties, or habitats identified for protection, additional mitigation options could provide greater flexibility. Recognizing scientifically supported adjuvant technologies across more crop protection products could help growers navigate regulatory requirements while protecting crop quality and yield.

4. What can a drift-reduction adjuvant realistically accomplish in orchards, vineyards, or berry fields?

Quattlebaum: “Most drift-reduction adjuvants create larger, more uniformly sized droplets as they leave the nozzle, making them less prone to drift. Some products also contain ingredients that reduce evaporation as droplets travel to their target. Combining droplet-size control with reduced evaporation creates an effective drift-reduction and delivery system.”

Butler: “Very small droplets are more susceptible to wind and environmental conditions, excessively large droplets may reduce coverage or bounce or run off target surfaces. The goal is to achieve the appropriate droplet spectrum. A quality DRA can shift more droplets into that optimal range, reducing drift-prone fines while maintaining coverage.”

Ferguson: “Spray drift reduction isn’t simply about making larger droplets; it’s about reducing the volume of the smallest, drift-prone droplets. Larger droplets can reduce spray efficacy because increasing droplet size reduces coverage.

“The right DRA can keep droplet size dialed in for proper coverage while reducing the volume of the smallest, drift-prone droplets. That helps orchard sprays stay where they are applied while maximizing pesticide efficacy.”

5. Is there a tradeoff between reducing drift and maintaining pesticide performance?

Quattlebaum: “There doesn’t need to be a tradeoff. Some products can improve agricultural chemical performance while also providing drift reduction.”

Butler: “There can be tradeoffs if droplet size is pushed too far in either direction. The goal is not simply larger droplets but a droplet profile that maximizes on-target deposition while minimizing off-target movement.”

Ferguson: “There can be. Growers should ask for verified wind-tunnel data showing that an adjuvant reduces the volume of small droplets without vastly increasing overall droplet size.

6. Are all products marketed for drift reduction essentially interchangeable for ESA mitigation purposes?

Quattlebaum: “I do not believe all products should be considered interchangeable because many different ingredients and combinations are used in DRAs. Each DRA needs to be tested, and reductions in buffer zones should be based on its capabilities.”

Butler: “Not all drift-reduction products perform the same, and growers should not assume products with similar claims will deliver identical results. When evaluating adjuvants, consider formulation quality, active ingredient concentration, performance data, compatibility with the spray program, and manufacturer support. Formulation differences can affect droplet size, drift reduction, coverage, and overall application performance.”

Ferguson: “There is no silver bullet. Different technologies reduce drift in different ways. Growers should look for a CPDA-certified product—they’re independently verified for claims made on the label. There are currently only 247 CPDA-certified products, a small fraction of the adjuvants on the market.”

7. What scientific evidence should EPA require before granting mitigation credit to an adjuvant?

Quattlebaum: “I believe high- and low-speed wind-tunnel testing has been required for herbicides. The real question is whether testing will be required for every formulation of every agricultural chemical active ingredient. That could place a significant burden on both adjuvant and crop protection product manufacturers.”

Ferguson: “Having served on the ESA Committee for the Council for Producers and Distributors of Agrotechnology (CPDA) since May 2023, I’ve seen how science affects EPA policy. Before DRAs received credit for herbicides in 2024, we had to demonstrate significant reductions through laboratory and field trials and published scientific papers.

“The data used validated ASTM and ISO standard testing methods and had to demonstrate proven drift reduction for a given class of drift-reduction adjuvant.”

8. Do EPA’s current mitigation approaches adequately reflect orchard and vineyard airblast applications?

Ferguson: “While airblast sprayers function differently than boom sprayers, they use similar or, in some cases, identical nozzle types. Droplet behavior after leaving the nozzle may vary somewhat, but the droplet’s physicochemical properties do not change across sprayer types.

“The right DRA can help maintain coverage while reducing the volume of the smallest, drift-prone droplets so they deposit and work as intended on the crop.”

9. Could ESA requirements change how your company develops, tests, labels, or markets adjuvants?

Quattlebaum: “Attune Ag has gone through the process of getting its adjuvants listed as DRAs for some herbicides. The new ESA requirements will require additional testing to gain DRA status for fungicides and insecticides.”

Butler: “As regulatory expectations evolve, the industry continues to evaluate how products are developed, tested, and supported with performance data. Ongoing product evaluation, quality assurance, and performance testing remain central to our development process.”

Ferguson: “Yes. The CPDA is finalizing an additional certification program for CPDA Certified Drift Reduction Adjuvants. A submitted product must demonstrate a 30% or greater reduction in the smallest, drift-prone droplets to be certified.

“Wilbur-Ellis plans to submit all products with a drift-reduction claim. We want customers to have confidence that the product they are buying will work as intended.”

10. What should fruit growers discuss with an adjuvant supplier or crop advisor as ESA-related pesticide restrictions evolve?

Quattlebaum: “Growers should look for products that perform the functions they already expect from adjuvants while also qualifying as DRAs.”

Ferguson: “A DRA is just one tool for keeping sprays where they are applied, maximizing efficacy, and complying with ESA and local regulations. Growers should ask their adjuvant suppliers for data showing that a product works as claimed.

“With costs rising, growers need to know what they’re buying. Compliance isn’t just about reducing spray drift; applications also need to work as intended. The right DRA can help accomplish both.”

Butler: “Plan before restrictions affect day-to-day operations. Growers should review crop protection programs to determine if products they rely on are subject to additional ESA-related requirements, and stay informed about pesticide labels, Bulletins Live! Two requirements, and regional considerations.

“Conversations with advisers and adjuvant suppliers should focus on practical options that fit existing operations, such as drift-reduction technologies, buffer practices, application timing, and equipment optimization. Evaluating options early can help reduce surprises and provide greater flexibility if additional mitigation becomes necessary.”