Trichoderma harzianum, a natural shield against soil-borne diseases

Date:01-26-2024

Trianum is a biofungicide based upon the unique fungus Trichoderma harzianum T-22. This bio-control solution colonizes plant roots and protects numerous indoor and outdoor crops against soil-borne diseases such as Fusarium, Pythium, Sclerotinia and Rhizoctonia. 

A unique strain

Trichoderma harzianum is a widely recognized fungus species used in plant protection products. 

However, each fungal strain has a different genetic make-up and is therefore unique when it comes to its adaptability to environmental conditions or its efficacy against specific diseases. 

Koppert is using the hybrid strain T-22 of Trichoderma harzianum, which was developed by merging two strains identified as strong biocontrol agents. One was considered an outstanding root colonizer, while the other strain was identified as an effective biocontrol agent of various soil-borne diseases under different stress conditions. This resulted in Trianum, a competitive root colonizer with effective disease control towards a wide range of targets in multiple soil types and climatic conditions.

How does it work?

After application, the spores of the fungus germinate, and rapidly starts to grow, creating a sort of protective barrier around the roots. This limits the chance of soil-borne pathogens to establish themselves on the roots. While growing, the Trichoderma strain uptakes many of the nutrients that the soil-borne pathogens also need, which means they are competing with them for resources and space. In addition, Trianum can also actively attack fungal pathogens by breaking down their cell walls, ‘feeding’ on them, which is called Mycoparasitism.

Additional benefits of Trichoderma harzianum

Besides the effects on disease control, this unique fungus can also contribute to the uptake of nutrients by the plant. Under stress, more dense roots covered by microscopic hairs can be observed. 

In addition to its impact on the soil and root structure, Trianum is also recognized for its ability, under specific conditions, to induce resistance in the plant shoots. This contributes to the weakening of foliar pests and diseases. Currently there is much research on this topic, but not yet exploited in bio-control. 

Exploring this additional benefit of Trianum is something we are actively researching, initiated through the doctoral thesis of a member of the R&D team. Subsequent progress was made in the past year, further advancing this research direction.

Trichoderma harzianum, a promising alternative

One of the main components for the success and effectiveness of Trianum, lays in the species. It is one of the most studied species, well known by its remarkable fast growth and competitive ability compared, not only with other plant beneficial species of microbes, but also key diseases. Its powerful root colonization facilitates the relatively fast root protection. From there, it extends with the control of diverse soil diseases much detrimental for Agriculture. 

Another intrinsic aspect of this species, not yet exploited in Biocontrol, is the well documented ability to induce the defences of the plant. This is actually a large field of research worldwide. The beneficial effects of the association of Trichoderma harzianum with the plant roots extends way beyond the soil, as it has a positive effect to the leaves of the entire foliage as well. When the plant roots are colonized, the defence in the plant leaves are also activated, debilitating the pests and diseases attacking them, which makes these threats more vulnerable to its control. Let’s note that, however, these biocontrol properties have been deeply studied with the ‘pure’ microbes, as they inhabit in nature. It remains unclear how much of all the Biocontrol abilities remain intact after they go through the complex process of making a biological crop protection product of it, in other words, to take it from nature to agriculture. 

Another key factor to make any potentially competent biocontrol species an effective product, lays on the production and formulation process. This ‘ultra processing’ needed to put these microbes in the hand of the growers is harsh for the microbes, as they come from soils where they are well stablished, thriving. 

Therefore last but certainly not least, it is the ‘know-how’ of these products. Keeping in mind that they are being (re)introduced in a different environment than their own, agricultural fields with diverse crops to be (re)associated with. And, multiple chemicals. Therefore, assessing what this microbe is capable of in these new ‘worlds’ is needed before bringing them into play. What targets can they tackle, what doses and moments of introduction are most effective, what conditions are most favourable and of course compatibility need to be closely assessed, to make sure growers are benefiting from the most effective bio-control solution. 

Production, formulation and application

Stated a bit oversimplified, the success of a microbiological product depends on three critical factors: its production, formulation and application. Production of fungal spores is traditionally based on solid state fermentation. Fungal mycelium develops in grains of cereals and subsequently, under the right conditions develops conidiospores that can be harvested. The method does come with some downsides as it is difficult to keep the cultivation conditions completely uniform throughout a complete batch and between different batches. Also, it is more prone to contamination by unwanted fungi and bacteria. To overcome these downsides, Koppert transitioned their Trichoderma production to liquid-based fermentation in bioreactors already years ago. The bioreactors and so called down-stream production equipment are wired with a wide array of sensors, allowing continuous monitoring of the production process and with that product quality and consistency. Product formulation is critical for unleashing the potential of biological agents under commercial circumstances. It should combine maximum viability of the microbial spores with maximum ease of application in the target markets. And it should be applied at the beginning of the crop cycle.

Easy to integrate in growers’ IPM strategy

Trianum can be easily included in the IPM strategy of a wide range of crops in different parts of the world. Paolo, Product Manager at Koppert states: ″One of the advantages of Trianum is the flexibility of use. It does not require any special application equipment. It is available in two different formulations to match various application systems used by growers. You can spray or add Trianum-P to an irrigation system or apply Trianum-G to the soil or in the furrow using a granulator.″ Another significant advantage of Trianum is that it is safe to use and can be tank mixed with many other solutions. ″We know the struggles that growers face in their day to day, so we do our best to not further complicate their life by investing in research aimed at understand compatibility with new actives and conditions for a successful adoption,″ concludes Paolo. 

Research and development

Research and development are major drivers of the movement towards more sustainable agriculture. Therefore, every product is the result of extensive research that starts from genes all the way throughout the in vitro controlled trials in the laboratory, to climate cells, to greenhouses and it ends with trials in the field to validate the results. Besides defining the potential target range, we also study the interaction between our products and the performance in a wide range of conditions, both abiotic and abiotic. For example, it is important to understand how the product grows and develops in different types of soils, under different climatic conditions, varying weather types and local agricultural practices. At the same time, there is a diversity of biological factors, such as variety of crops, cultivars and diseases strains the product will have to face. Koppert addresses this by ending their research at the field, performing series of standardized experiments in different parts of the world and across several growing seasons. The research does not end when a product is made available to growers. The search for a more stable, resilient and more widely applicable natural solution continues by optimizing product applications not only in terms of the highest achievable efficacy, but also in terms of ease of use for the growers and sustainability. And, they constantly seek for USP’s; what additional benefits can their products offer to growers. In the end, the most important is the solid research approach they follow at Koppert which boosts the confidence of growers in their biological crop protection solutions.