When powdery mildew infects pumpkin fields, farmers' yields, incomes, and the food supply are all at stake. At the same time, pressure is increasing to reduce the use of conventional crop protection products. The search for more sustainable solutions therefore leads to a seemingly simple question: What if biological and chemical active ingredients could combine their respective strengths?
This is precisely where Evonik's work begins. The key factor is not only which active ingredients are used, but also how they are formulated. Between the laboratory and the field lies a frequently underestimated science: the art of packaging active ingredients in a way that keeps them stable, allows them to be applied effectively, and enables them to deliver their benefits exactly where they are needed. Recent studies by the company show that this area offers considerable potential.
Limits of Biological Crop Protection Products
Biological crop protection products are experiencing strong growth worldwide. Many regulatory authorities promote environmentally compatible solutions, consumers increasingly value sustainability, and at the same time the number of resistant plant pathogens continues to rise. Microorganisms are thought to be more difficult for pathogens to develop resistance. Those that protect plants against pests and diseases are therefore considered a promising additional tool compliment conventional active ingredients.
However, biological products also have limitations. Their performance can be more dependent on environmental conditions than that of conventional chemical fungicides. While a synthetic active ingredient often performs very reliably, living organisms are more sensitive to temperature, humidity, and the way they are formulated.
This presents researchers with a challenge: How can biological and chemical crop protection products be combined so that both benefit from one another?
Fungus Meets Modern Chemistry
The research focused on two very different players.
The first is Trichoderma harzianum, a soil fungus that has been well known in biological agriculture for many years. Rather than controlling pathogens through toxicity, it relies on biological strategies. It competes with harmful fungi for space and nutrients while simultaneously activating the plants' natural defense mechanisms.
The second partner is azoxystrobin, one of the most widely used fungicides in the world. This active ingredient directly interferes with the energy metabolism of plant pathogens and prevents their growth. Its effectiveness is well documented, yet agriculture and industry are looking for ways to reduce dependence on such products over the long term.
The researchers' idea was to bring both active ingredients together in an integrated system, thereby delivering two different modes of action to the field at the same time.
The Invisible Key: Formulation
To outsiders, formulation may sound like a technical detail. In reality, it often determines whether a crop protection product succeeds or fails.
An active ingredient must be finely distributed, remain stable, be easy to store, and adhere as uniformly as possible to plant surfaces after spraying. With biological products, an additional challenge exists: living microorganisms must survive both storage and application.
Evonik therefore developed liquid formulations known as dispersion concentrates. Various formulation aids ensure that the active ingredients are distributed uniformly, that particles remain stable, and that the biological active ingredient retains its viability. At the same time, they improve wetting and spreading across the leaf surface.
As a result, formulation aids themselves become a critical component of product performance. They do not directly control pathogens, but they create conditions that allow the active ingredients to reach their full potential.
Stability as a Prerequisite for Success
Before a product can be tested in the field, it must demonstrate that it can withstand storage and transportation.
The researchers therefore evaluated the combined formulation at temperatures of 25°C and 40°C. No visible phase separation was observed. The flow properties also remained stable throughout the testing period. Most importantly, however, another result stood out: the viability of the Trichoderma spores was maintained even after several weeks.
This may sound unremarkable, but it is a fundamental requirement for biological crop protection products. A microorganism can only provide benefits in the field if it arrives alive.
The Practical Test in Pumpkin Fields
Ultimately, what matters is not performance in the laboratory but results under real-world conditions.
Field trials in North Carolina, USA, on pumpkins infected with powdery mildew. The plants were treated multiple times in order to compare different formulations. The results surprised even experienced crop protection experts.
The newly developed Trichoderma formulation delivered significantly better performance than a commercial reference product, despite containing approximately two and a half times less biological active ingredients. In other words, less fungus resulted in more protection. This demonstrates how Evonik’s additives made the microbial fungicide more efficient.
Equally remarkable was its combination with azoxystrobin. The joint application achieved disease control comparable to that of a conventional fungicide treatment. At the same time, the amount of chemical active ingredients could be gradually reduced. Even when reduced to 58 percent of the standard application rate, efficacy remained comparable.
More Than the Sum of Its Parts
The results point to an important conclusion: The success of a crop protection strategy is determined not only by its active ingredients, but also by how they are formulated.
Improved spreading across the leaf surface, uniform dispersion, and the preservation of viable microorganisms creates advantages that translate directly into field performance. The researchers therefore describe a functional synergy between biological and chemical active ingredients that is enabled by formulation.
For farmers, this could mean effective disease control while reducing the use of conventional fungicides. In addition, multiple modes of action offer an extra advantage in the fight against resistance, one of the greatest challenges facing crop protection worldwide.
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A New Role for Formulation Aids
The study clearly demonstrates how the role of formulations is evolving. For many years, formulation aids were viewed primarily as technical companions to active ingredients. Today, they are increasingly becoming a strategic tool for connecting biological and conventional approaches.
This highlights an insight that extends beyond crop protection: Innovation often arises not only from new active ingredients, but from intelligent systems that enable existing technologies to work together more effectively.
For the agriculture of the future, this may be a key principle. Not biological or chemical, but biological and chemical. Combined in a way that delivers greater impact with less active ingredients.