Nicolas Aveline from the IFV’s Nouvelle Aquitaine Centre explains what biocontrol is in 4 questions and answers.
The winegrowing sector is committed to reducing phytosanitary inputs with biocontrol products. Where do we stand today?
The objective of reducing phytosanitary inputs is part of the Ecophyto plan. Alternative methods to the use of synthetic products, using biocontrol products, are beginning to emerge, but these new techniques that help reduce the use of phytopharmaceutical products are still at the experimental stage. We try to work alternately with synthetic products. Biocontrol products have a special status because a definition of them is included in the Law on the Future of Agriculture in 2014. There is a list of products set by the Ministry of Agriculture, and it changes every quarter.
What are biocontrol products?
These can be micro-organisms, i.e. bacteria, yeasts, fungi, viruses, etc. Biocontrol products also include chemical mediators – pheromones or kairomones – and, lastly, substances of natural origin, whether plant, animal or mineral. As you can see, they are sometimes very far removed from conventional products, which are often biocidal and highly targeted, like some insecticides, for example. In biocontrol, we are dealing with products that act using other modes of action. They are not necessarily biocidal and can also be defined as stimulators of natural plant defences, repellents, environmental modifiers, etc.
Can you provide some examples?
With reference to competing micro-organisms, we can, for example, work with bacteria or fungi that will colonize the environment to prevent diseases from taking a hold on crops. In the vineyard, there is the example of bacteria that act as competing microorganisms with botrytis. However, we cannot yet speak of consistent results with this type of product for the time being. If we take the case of repellents based on clays, such as kaolinite used against leafhoppers, this is another example of the biocontrol of pest populations. The modes of action and origins of biocontrol products are so diverse that it is sometimes difficult to classify them in terms of their efficacy. This is also due to the fact that we are not yet used to working with these products.
What are the difficulties encountered in the use of these products?
Basically, the aim is not to eradicate pests, but to play on the balance between crops and pests. From a philosophical point of view, biocontrol is sometimes difficult to integrate because depending on the climate, the “terroir” and parasite levels, it does not always work. That said, biocontrol has been given the green light because specifically French legislation exists on the notion of reducing phytosanitary inputs. There are great expectations on the part of winegrowers and the whole sector and these products have developed strongly since an official list was drawn up. Things have changed a lot.
The challenge today is to transfer biocontrol methods to the winegrowers in terms of how these products are used, in order to obtain better results and limit the use of conventional synthetic products.
Is biocontrol heralding in the end of synthetic products?
It would be an illusion to believe or predict that biocontrol will replace conventional methods of controlling vine pests and diseases. That said, we have to add everything together, that is combine and integrate all the methods we know. Things are going to get very technical; we’ll be doing agronomy rather than agriculture. What is certain is that we are not heading for the simplest solution, but we have no choice. And winegrowers, who were used to using simple products, have now been won over to these changes in practice. That was not the case 10 years ago!
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