BASF presented technical results in 2026 for a new approach to simplifying emulsifiable concentrate (EC) formulations used in crop protection: using Lutensol® TO surfactants to perform both emulsification and adjuvant functions within the same formulation. Evaluated by BASF researchers in Germany, the technology is designed to reduce the number of components required to build stable formulations while maintaining-or potentially improving-spray performance on plant surfaces. The development matters because fewer formulation components could mean less complexity, fewer compatibility challenges and more efficient product development for crop protection manufacturers.

Emulsifiable concentrates remain an important formulation type in crop protection because they can accommodate relatively high concentrations of active ingredients and form emulsions when diluted in water. Building a robust EC, however, often requires a combination of surfactants with different roles. Conventional systems described in the BASF research include emulsifiers based on alkylbenzene sulfonates (ABS) and ethoxylated castor oil, while additional adjuvants may be incorporated to improve biological performance.

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That approach can increase formulation complexity. According to the research, additional adjuvant components in certain EC systems based on aromatic solvents such as solvent naphtha can account for as much as 20% by weight of the formulation. BASF's concept is to consolidate part of those functions into a single surfactant family: Lutensol TO can provide emulsification and adjuvancy simultaneously, potentially reducing the need for separate specialized components.

Simplifying the formulation starts with proving stability

Before evaluating performance on plants, BASF subjected the formulations to stability testing. The experimental design combined a CIPAC MT 36.3 rapid screening test with a dynamic cold recirculation test. In the first stage, the EC was diluted to 5% in water at 21°C, vortexed for one minute and visually inspected for emulsion stability.

The second test was more demanding. A diluted emulsion was continuously recirculated for six hours at approximately 4°C through a system incorporating a pump, a 140-micron filter and pressure monitoring. If unstable particles or deposits formed, residues could accumulate in the filter and cause system pressure to rise.

What the stability tests showed

Source: AgroLatam analysis based on experimental data reported by BASF.

The results showed that the evaluated Lutensol TO formulations remained stable under those conditions. Less than 1 mg of residue accumulated on the filters, and no increase in pressure was observed, according to the reported testing. That finding is significant because simplifying an EC formulation only becomes commercially meaningful if physical stability can be maintained during dilution and under demanding operating conditions.

The experiments covered active ingredients with different physicochemical profiles. BASF evaluated formulations containing difenoconazole, oxyfluorfen and trifloxystrobin at 15%, using solvent naphtha with Lutensol TO 6 or TO 8. Additional systems included penconazole, tebuconazole, oxyfluorfen and pyraclostrobin, combined with different solvents and Lutensol grades.

Crop protection formulations evaluated

Source: AgroLatam analysis based on BASF formulation data.

Another notable finding was the technology's performance with different solvent systems. BASF reported emulsification capabilities not only with traditional aromatic solvent systems but also in formulations using fatty-acid esters and amides. This could give formulators greater flexibility when designing EC products around different active ingredients and formulation requirements.

The chemistry also has relevance for international product development. Lutensol TO surfactants are based on iso-C13 alcohol and ethylene oxide, and BASF reports that the evaluated materials are registered or exempt under relevant inventories or frameworks in China and the European Union, as well as under TSCA and EPA 40 CFR 180.910 in the United States. This does not mean that a finished pesticide formulation is automatically approved-the final product remains subject to applicable registration requirements-but it is an important consideration for formulators developing products for multiple markets.

From formulation stability to soybean and wheat performance

The second part of the research addresses the question most relevant to growers and crop protection companies: can a dual-function surfactant do more than simply stabilize the formulation? BASF compared droplet behavior on soybean and wheat leaves. The results showed that Lutensol TO surfactants significantly reduced the dynamic contact angle on soybean leaves, improving wetting and spreading across the leaf surface. On wheat, the testing also showed greater droplet retention compared with single-function emulsifiers.

From the spray tank to the leaf

Source: AgroLatam analysis of BASF experimental results.

The images from the experiment help explain the mechanism. A droplet with a lower contact angle spreads farther across the leaf surface, potentially increasing the area reached by the spray solution. Better spreading alone, however, does not necessarily translate into biological efficacy, so the researchers also investigated foliar uptake.

BASF used chlorophyll biofluorescence testing with bentazone, a photosystem II inhibitor, to evaluate absorption and redistribution within plant tissue. Within the Lutensol series, TO 5, TO 6 and TO 7 produced the highest relative absorption levels in the reported experiment. The results suggest that differences in surfactant structure can influence not only formulation stability but also the interaction between the spray solution, active ingredient and plant surface.

Different Lutensol grades target different formulation needs

The final step was to determine whether those physicochemical effects could translate into biological disease control. BASF conducted greenhouse testing against brown rust in wheat, using an azoxystrobin SC formulation and comparing Lutensol TO 8 with benchmark adjuvants. The experiment included preventive and curative applications using an adjuvant rate of 200 mL/ha and a spray volume of 200 L/ha.

According to the reported results, Lutensol TO 8 achieved disease-control performance comparable to high-performing benchmark adjuvants under the conditions of the greenhouse trial. The result does not establish that the same response will occur with every active ingredient, crop or field condition, but it provides evidence supporting the dual-function concept beyond physical formulation stability.

For the U.S. crop protection industry, the broader significance lies in formulation efficiency. Developing pesticide products increasingly involves balancing active ingredient performance, physical stability, manufacturing requirements, regulatory considerations and application characteristics. Reducing the number of components while retaining multiple functions could therefore have implications from the formulation laboratory to the spray tank.

The concept also fits into a wider industry trend toward more sophisticated formulation technology. As crop protection products incorporate new chemistries, biological ingredients and increasingly complex mixtures, the ingredients surrounding the active substance can play a growing role in determining stability, delivery and ultimately field performance.

BASF's work does not suggest that one surfactant can replace every emulsifier or adjuvant across every formulation. Rather, it demonstrates the possibility of combining two traditionally separate functions within a single formulation component. BASF positions TO 6 toward stronger adjuvancy, TO 8 as a balanced option and TO 10 toward stronger emulsification.

If that performance can be replicated across commercial products and field environments, dual-function surfactants could give crop protection formulators another route to reduce formulation complexity while maintaining stability and biological performance. In an industry where attention typically focuses on the active ingredient, the next efficiency gains may increasingly come from the less visible chemistry that determines how that active ingredient is formulated, delivered and ultimately reaches the plant.