Root health from the perspective of seed treatment development

Monika Scheller, global technical manager for Syngenta Seedcare, is responsible for the development of new seed treatment fungicides. She works together with internal and external scientists and field trial researchers around the globe looking for solutions to the key diseases that threaten seedling emergence and establishment. Root Health is a main focus and field of research for Monika and her team.

Looking at field trials worldwide, what would you say are the biggest threats to Root Health?

There are many biotic as well as abiotic factors influencing Root Health. Pathogens, insects and nematodes are a major threat to the healthy roots in many crops and regions. Also, abiotic factors – such as soil moisture or nutrient availability – can highly influence Root Health. From a pathologist’s perspective, soilborne pathogens such as Fusarium, Pythium and Rhizoctonia represent the biggest threats. These diseases can affect the development of a good and functional root system from the very early stages of the plants development or, in the worst case, completely inhibit the emergence of seedlings.

Are there regional differences with respect to the importance of these pathogens?

Although Fusarium, Pythium and Rhizoctonia are ubiquitous, the severity of the diseases caused by these pathogens depends on the region, the crop and environmental factors. Despite the agronomic importance of these pathogens, there are huge differences in grower awareness of them. Growers often don’t know which pathogens prevail in their fields. There is, for example, little awareness of Rhizoctonia, even though surveys carried out by Syngenta and different collaborators show that Rhizoctonia is extremely widespread and can cause severe crop losses. In contrast, growers are highly aware about the impact of Pythium in corn.

Why do you think that Root Health in the early stages of the plant’s development is so important to the grower’s yield?

The emergence and first weeks after emergence are crucial times in the development of plants and, thereby, of the plant’s ability to produce yield. Consequently, these stages are effective times to protect the plant and allow the formation of a good root system. If roots aren’t protected from soilborne pathogens at these early stages, it will be reflected in plant stand and yield.

What is the main challenge in trying to promote a healthy root system with Seedcare products?

We often say “out of sight, out of mind.” Neither roots nor soil pathogens are visible when looking at a field. In contrast, leaf diseases often have very characteristic visible symptoms that can easily be recognized. In the past, the focus in plant protection was on the above ground parts of a plant. With soil diseases, growers often only see reductions in yield, but no lesions on the plant. The only visible symptom is sometimes reduced emergence or patches with reduced plant growth. Diseases that don`t kill the plant, but that affect the development, can easily be misinterpreted as a lack of moisture or nutrients. This is one of the reasons why the damage caused by Rhizoctonia is often underestimated. Rhizoctonia doesn’t necessarily kill the plant, but can still have a significant effect on yield by inhibiting the development of a healthy root system. In order to raise the awareness of damage to roots caused by pathogens, you need to make the roots visible.

What means do you use to make the root system visible to the grower?

During the development of VIBRANCE® seed treatment to protect against Rhizoctonia, we often took the growers and colleagues to the field, dug out roots and looked at them. This gave growers and colleagues something tangible and increased their awareness of the effect soilborne pathogens can have on roots when you don’t protect them (e.g. with a seed treatment). Meanwhile, there are also scientific methods to visualize roots, such as the Rhizotrone technique or various X-ray imaging techniques.

In September Syngenta hosts its second international Root Health Forum, this one in Beijing. Plus there have been seven regional meetings during the last year. What is the idea behind these Forums?

There are several ideas behind the Root Health Forums. The Forums bring experts from various fields of research and regions together and trigger discussions around Root Health, the different threats to it and possible improvements of Root Health in general. The Forums also bring awareness to this topic in the scientific community. For Syngenta, it’s important to demonstrate the commitment to Root Health and improve the link and collaborations with the scientific community. We also hope to get a better feeling for where the biggest need for solutions might be and ideally bring up new ideas together for improving Root Health in the future.