“More stable, compatible formulations with better distribution of the active ingredient are more efficient…”
Marcia Werner is the global director of research and technology for agribusiness at Croda, an English multinational chemical and specialty company. Werner is a biologist graduated from PUC, with a specialization in agronomy from the Federal University of Viçosa.
Marcia Werner, director of research and technology for agriculture at Croda
AgriBrasilis – What are the trends in the development of agrochemical formulations?
Marcia Werner – Agrochemicals have different physical-chemical characteristics and modes of action, which requires adjusting the type of formulation according to the situation. With restrictions on the registration of toxic products and bans on some chemicals, there are fewer active ingredient options available. Furthermore, pest resistance to certain modes of action has led to the development of formulations combining multiple active ingredients and investment in more effective delivery systems such as nanotechnology and encapsulated. Another major trend, driven by companies committed to sustainability, is the development of formulations that are less toxic to humans and to the environment, which preferably use renewable, biodegradable and/or microplastic-free raw materials.
AgriBrasilis – The majority of pesticides in Brazil belong to the EC, SC, SL and WG formulations. What do the acronyms indicate and what are the differences between these products?
Marcia Werner – SL (Soluble Concentrate) are formulations where the active ingredient is completely soluble and stable in water. This type of formulation is favorable because it is water-based, easy to produce and low cost. However, there are only a few active ingredients that can be formulated in this way; glyphosate is an example.
For non-water soluble ingredients, the preferred formulations are EC, SC and WG. EC (Emulsifiable Concentrate) are solvent-based formulations, where the active ingredient is solubilized and emulsifiers are added for adequate distribution in the spraying solution.
SC (Concentrated Suspension) is the main choice currently, being water-based, solvent-free, with the active ingredient suspended in fine particles stabilized by surfactants and polymers.
WG (Dispersible Granules) are solid formulations in granules, where the active ingredients are dry-milled with surfactants and polymers, providing high wettability and suspension of particles in water. This type of formulation allows you to concentrate the product and reduce packaging, transport and storage impacts.
AgriBrasilis – What makes one formulation more efficient than another?
Marcia Werner – Products with the same active ingredient may present different results due to the type of formulation and its components. More stable, compatible formulations with better distribution of the active ingredient are more efficient. The addition of adjuvants to the formulations can also improve the biological efficacy of the active ingredients.
AgriBrasilis – What factors affect the compatibility of phytosanitary products and why?
Marcia Werner – Incompatibilities occur when products are mixed without prior knowledge of possible chemical reactions between active ingredients and/or components.
Physical instability can be caused by the quality of the dilution water and the presence of electrolytes, which can degrade active ingredients and components or alter the formulation’s stabilizers, resulting in flocculation and sedimentation, which clog spraying nozzles and compromise application. The order with which the products are added to the spraying solution and the low volume of dilution water can intensify these problems.
AgriBrasilis – Adjuvants, for example, do not have their own legislation in Brazil. In this sense, how do you see the regulatory aspect for agrochemical components?
Marcia Werner – Current regulations require that all components of the formulations be described, including their proportions of use. This restricts possible formulation adjustments, as any change requires a time-consuming and costly process for companies. This inhibits, for example, improvements in stability or the addition/replacement of components with more efficient, sustainable or lower-cost options.
It is contradictory that there is no regulation for adjuvants in Brazil, while there is an overcontrol of the formulation components. I find it interesting that there should be more flexibility in the component registration process, but it is important that there are criteria to ensure that the final product does not have a negative impact on human and environmental toxicology.
AgriBrasilis – Why are there adjuvants used in the formulation industry and also adjuvants used in the field by farmers? Why don’t these products come ready from the factory?
Marcia Werner – A big factor is the lack of space in the formulation: adjuvants need a minimum dose to take effect and, sometimes, there is no space in the product’s composition.
The industry has evolved in the development of multipurpose components, more effective adjuvants and formulation technologies that allow greater incorporation of adjuvants, such as microemulsions and oily dispersions. However, in addition to the technical barrier, there is an issue of cost and competitiveness of the products.
The incorporation of adjuvants in formulations occurs mainly in new launches, in products with higher added value, where the choice of adjuvant is optimized for the active ingredient. Although it is ideal to incorporate adjuvants already in the product composition, adjuvants added in tank mixes by farmers will not fall into disuse. They remain important allies in the application technology and impact on the biological effectiveness of agricultural pesticides.