The problem of excessive root growth in tomatoes and aubergines worries many growers. The plants affected show severe growth and poor fruit settling. The widespread degradation results in an uneven crop and the extreme root growth on stonewool pots sometimes allows water to drip down the pots instead of keeping it in.
Growers affected say they lose about 5-10% of the production, as well as hundreds of hours of additional labour per hectare for crop maintenance and follow-ups. The problem appears in many countries with protected cultivation, both within and outside Europe. Efforts to fight the Agrobacterium rhizogenes (now called Rhizobium rhizogenes) which causes it seem to be of no avail.
Good hygiene in the crop rotation helps reducing the chance of infection, but once the damage starts, trying to control the pathogen with all kinds of disinfectant products (based on chlorine, peroxide, etc.) often brings no results. Unfortunately, in many cases, these treatments can even be counterproductive. It is a bit like the fight against antibiotic-resistant bacteria.
All attempts to keep everything 'sterile' during the cultivation process appear to be doomed to fail. Nature probably has a better answer. By working on the development of a diverse and appropriate mix of beneficial bacteria, fungi and other microorganisms (called soil food), from the very beginning of the cultivation process it is possible to improve the resistance of the root system. A rich soil food also helps in the fight against Rhizobium. Independent research by WUR, among others, confirms that biodiversity in the best strategy to adopt to control Rhizobium. In English greenhouses, this approach has already made the problem more or less a thing of the past.
Koppert is collaborating with WUR in a research project to gain a better insight into the mechanisms and conditions for a successful application of a range of micro-organisms and biostimulants in the root environment. Initial results confirm that the presence of (a mix of) the appropriate microorganisms / biostimulants certainly helps against Rhizobium when correctly applied (right place, right time). An irrigation strategy that ensures sufficient oxygen arriving to the root system is also important for the development of beneficial organisms therein.
The above mentioned benefit of biodiversity in the root zone is also visible in practice. Furthermore, there are perceptible differences between various substrates in the development of the infection. Perennial substrates (with a more diverse soil food) appear to be more advantageous than new (one-year) substrates.
The last word has not yet been spoken, but Koppert, thanks to its experience with Natuulijk Telen (Natural Cultivation - Natugro) will help in making your fight against Rhizobium more manageable in a natural way, with targeted products and advice.
Source: Koppert
For more information:
Koppert Biological Systems
Veilingweg 14
2651 BE Berkel en Rodenrijs