ALTERNATIVES TO PESTICIDES -2- THE CROP MONITORING
We can't really classify the crop monitoring as an alternative to pesticides, but I decided to make it the starting point of this series because it's the foundation of Integrated Pest Management, and of phytosanitary protection in organic farming.
None of the methods, techniques, and novelties that will come into it, will develop or function properly without this fundamental step.
Any crop monitoring implies the integration of a rarely commented and yet essential aspect for a modern, productive, respectful, healthy and sustainable agriculture: the knowledge.
Sustainable agriculture is an agriculture of science and knowledge.
The knowledge of the crop first, its physiological cycle, its climatic adaptation, its agronomic requirements, its nutritional needs, its sanitary and physiological sensitivities, its compatibility with surrounding crops, etc.
The knowledge of the soil, which is the vital support of the crop, in order to take into account the potential susceptibility factors (pathogens, risks of nematodes, radicular asphyxia, etc.), and to know the nutritional contributions of the soil to the crop (including the risk of deficiencies).
The knowledge of adverse risks, especially climate risks, diseases, pests.
The knowledge of crop protection auxiliaries (insects, fungi and predatory vertebrates), which will be useful in helping to solve specific problems of the crop.
The knowledge of the environment of the growing areas, to know what help it can bring us (favorable areas for the development of some auxiliaries for example), or what constraints it assumes (the proximity of illuminated areas may increase the presence of some nocturnal Lepidoptera, harmful to crops for example), and what the farmer will have to do, or not to do in order to take into account this environment while getting the best possible result of his activity.
It should be noted that this level of training and knowledge, now recognized as the essential starting point for any evolution of agricultural production towards virtuous practices, is a recent (and not yet fully generalized) achievement in the most developped countries (from the second half of the 20th century), and still to be acquired in much of the world. Agriculture universally remains as one of the most backward sectors of human activity and the world economy, in education, training and development.
Picture: Issiaka Konate (ARAF - Dogon Plateau), Mali
Once this knowledge has been acquired and the crop put in place, the farmer will have to implement a process, often complex, which will allow him to put his crop in the most favorable conditions for its development and production, both in terms of quality in quantity.
One of the key points will be the protection of the crop against diseases and pests.
- He has first to implement all available means to prevent health attacks from occurring. It's prophylaxis. This will be the removal of contaminated remains from previous or adjacent crops, pruning, cleaning of surrounding areas, etc.
- He will then implement observation systems, so as to detect attacks as early as possible. It's monitoring. It's the setting up of monitoring traps, observation protocols, counting, climatological recordings, etc.
- He will link observations and counts with reference levels called "nuisance thresholds", which vary according to the crop, the region, the type of parasite and the time. He will determine in this way from what moment a present threat becomes really dangerous and presents an economic risk. This is the notion of intervention threshold.
- At the same time that he observes the populations of pests, he observes the presence of predators of all types. They are insects, mites, fungi or vertebrates (birds, snakes, carnivores) that feed on different risks present on crops. Their presence can greatly reduce or even completely eliminate the threat of a pest population. It's the use of auxiliary organisms.
- He will choose the intervention method on a case by case basis. He will use pesticides, natural or synthetic, choosing them for their effectiveness, their side effects and the risks to the environment and health, when no other means will solve the problem. This is the intervention decision.
Each crop, each period of the physiological cycle, each type of climatic conditions will require a suitable response.
Monitoring of population levels of diseases and pests and their auxiliaries allows deciding the best intervention technique, if it is needed, and its optimal timing.
THE CHOICE OF PRODUCTS
When I started in agriculture in the early 1980s, the available phytopharmacopoeia included a large number of highly versatile synthetic molecules. When you sprayed against an attack of aphids, all that was present (Diptera, Hymenoptera, Coleoptera, Lepidoptera and other harmful or useful insects) was also eliminated. The respect for equilibrium was not on the agenda, and anyway it would have been difficult to try, because none of available and allowed pesticides, or almost, was selective.
Gradually, more and more specific products appeared, reducing the versatility, therefore the risks of "cleaning" untimely.
It must be pointed out, however, that at the same time certain problems have appeared, or reappeared, often known as described in the old treaties, but hitherto generally controlled by the versatility of phytosanitary products.
The information to the farmer has also increased a lot.
Until the 1990s, he knew only the risk for the user (and often only partially), and the time to use before harvest.
Gradually, the farmer has received ever more comprehensive information about health, the environment, and the conditions of use.
With improved measurement techniques and lower costs, pesticide residue controls have become more widespread. Standards for each product and type of food have been established.
The most versatile products have been banned for the most part.
While it is true that until the end of the 1980s it was usual (but not systematic) for farmers to spray by schedule, without really worrying about the presence of diseases or pests, let alone auxiliaries, it's no longer the case today, for several reasons:
- The level of training and knowledge of farmers has risen sharply.
- The improvement of technical support to farmers by public, private or cooperative-type structures also makes it possible for less-educated farmers to progress.
- Social pressure around sustainable agriculture with minimal impact on health and environment has literally exploded in recent years.
- Concern about the impact of farming practices by the farmers themselves has risen sharply.
- The legislation is tightening each year a little more, both on pesticide authorizations and conditions of employment, and controls and sanctions also, at least in rich countries.
- Supermarkets, which control the majority of consumer markets in industrialized countries, oblige their suppliers to follow and comply with specifications that are currently very focused to health and environmental risks. Controls are numerous and penalties are severe.
- The cost of phytosanitary protection is high, and significant savings are possible (in comparison with a systematic schedule spraying program) thanks to a good management.
- Many biological or very specific pesticides are appearing on the market, with specific technical requirements that request very precise conditions of use, but which allow the farmer good technical results without the risk of residues.
It's also important to note that the pest thresholds used in the 1980s and 1990s had to be revised in most cases because of the evolution of available solutions.
Indeed, when the farmer had very versatile products with a significant shock effect, he could wait for harmful attacks to reach relatively high levels.
Today it's very different, because solutions rarely have a powerful shock effect, forcing the farmer to anticipate.
The philosophy of protection is no longer to "let grow up and clean everything up", but rather to "prevent the problems from gaining momentum", which would make them very difficult to solve.
This paradigm shift also has a very direct impact on how the farmer focuses on protecting his crops, because he knows that if he is not able to avoid the development of some problems, the economic consequences can be extremely serious.
In short, the monitoring of the crop has long been an important technical point for the farmer.
With the many changes of recent years, it has become a real working method that occupies an essential place in the protection of the crop, and in obtaining a satisfactory technical result.
Yes, if it is true that crop monitoring is not, in itself, an alternative to the use of pesticides, it's however a key factor in the success of the crop with a minimum of pesticide interventions.