lundi 1 février 2016

67- Plants protection -5- The good use of pesticides


A world without synthetic pesticides is not currently possible, whatever some say, especially because
-       World population has grown exponentially in recent decades,
-       Food needs have skyrocketed
-       Many phytosanitary problems which could seriously affect agricultural production currently don't have other effective solution
-       Available agricultural land for food production are reduced (urbanization, desertification, biofuels production, production of biological pesticides, etc.)
Pesticides available to organic farming are progressively more numerous and cover increasingly diverse needs. However, they are not yet sufficiently numerous and versatile to meet all needs.

Yet, as I explained to you in my last article ( , it would be enough to revise the requirements of organic agriculture, accepting "pesticides-copies", which are none other than synthetic making of natural molecules, to cover most of the shortcomings of biological pharmacopoeia.
But here we enter a highly political area, where logic, long-term vision, the real consideration of environmental issues and simple consistency, pass in the background in front of the search of power and manipulation of opinion in an ideological objective.

All this to say that, in the present state of agriculture, it is entirely possible to make a conventional farming, very respectful of environment and health.
But it is also to say that the risks associated with pesticide use are the same for natural products as synthetic products.

Some precautions are of course necessary to minimize the impact of pesticides.
Again, these recommendations are valid for both synthetic pesticides and biological pesticides. If an active ingredient kills pests, it is likely that it also kills beneficial insects or has undesirable side effects, either if it is derived from synthetic chemistry or if it is a plant extract.
For the use of all types of pesticides, certain precautions are necessary to ensure that the impact is minimal.

So, what are correct conditions, when talking about pesticides?

It covers several key points:

A trained staff: all people involved have to be properly trained, both for mandatory training for handling products, for the observation of crops and recognition of phytosanitary problems. That means the farmer himself, his observer, the tractor drivers, storekeepers and others who may have a role in plant protection.

The precise determination of needs: through staff training, the farm is monitored by a specific routine to these crops, to determine their phytosanitary status and potential risks at any time. For this we use all available means, visual surveillance countings, trapping control, calculation of crop cycles and plant health issues, agricultural warnings, climate data. This way, we monitor all potential risks, as well as evolution of the helpful fauna. These controls are put in relation to the risks to the crops, evolution probabilities and available action levels. This is the systematics which will enable the farmer to take the 
decision to wait or intervene, and in what way.
Monitoring trap for mediterranean fruit fly.

The precise product: each product has specific characteristics, and can meet a range of well-defined requirements. Uncontrolled side effects are those that cause the real environmental problems. It is essential to always use the most suitable product for the situation. A good spray efficiency is the best way not to need to do it again.

The precise moment: this is the moment when the solution proposed will be more effective on the problem to solve. Every situation is different. Apply the product too soon reduces its effectiveness because the target is not at its optimal time of sensitivity. Moreover, at least in the case of insecticides, wait often allows beneficial insects to settle and resolve the problem without the need to spray. Apply the product too late, puts it in a situation where it may be insufficient, so it could be necessary either complete it by another product, or spray a second time. Less efficiency for superior economic and environmental cost.

Suitable climatic conditions: we'll always spray without wind to avoid the product drifts out of the crop, without rain to prevent runoff on the ground, and with suitable temperature conditions. It is common during summer, to have to spray by night to avoid intense heat, which can seriously reduce the effectiveness of applications. But it can be difficult to combine all spraying factors and weather conditions are not always easy to comply.

The precise dosage: a too low dose will have insufficient efficacy and may cause the need for a second application. Moreover, the routine use of too low doses can lead to the emergence of resistant strains (insects surviving to the spray gradually immunize to the product). A too high dose will solve the problem, but with a high economic and environmental extra cost, both harmful and unnecessary.

The alternation of products: it is a basic rule in the use of pesticides, chemical or biological. It is important to alternate products, varying modes of action, so that the targeted problem has minimal risk for developing resistance.

The compliance with the conditions of use: each product, before being marketed, goes through many stages of studies to determine its terms, on each of the crops for which it will be allowed. This applies to pre-harvest deadline (to reduce or avoid potentially present residue upon consumption), to the distances to water points, to the time limit before the entry of people or animals in sprayed plots, etc.

The quality of application equipment: this is what will allow to respect the precise dosage and specific moment. It is therefore fundamental. These are mainly the type of machine and the type of nozzles. The machine must be appropriate to the crop. We don't spray with the same equipment a wheat field, a vineyard or a cherry orchard. But it is also the number of machines that the farm needs, to react quickly in case of problem, so it doesn't take serious proportions because of under-equipment, and slow reaction.

The quality of personal protective equipment (PPE): these are the gloves, boots, helmets or respirators, protective suits or tractor cabins. It is essential that they are appropriate and in good condition. It is also essential that persons handling these products, which are the most exposed, wear them (I say this because many applicators do not like to wear them, and thus take unnecessary risks). Under certain conditions, especially in summer when it is hot, they can be quite uncomfortable. One of the most sensitive points is the choice and the condition of the respiratory filters.

The precautions when storing pesticides: Each farm must be equipped with a safe storage place, so that products are safe from the rain, cold, heat, in short, all conditions which could affect its preservation. The place must be fire resistant, equipped with fire extinguishers, and be able to contain spillage. Similarly, access should be limited to a few people trained in handling pesticides.

The precautions when preparing the phytosanitary mix: a well done filling and washing point allows to control the risk of pollution of soil and watercourses. The use of appropriate measuring instruments, accurate enough and in good condition, provides the right mix of products. Moreover, it is the moment of filling of the tanks that the product is the most dangerous, since the package is opened and the product is concentrated. It is therefore essential that all precautions be taken at that moment.

The proper management of effluents and packaging: it is a sometimes overlooked part. Yet it is very important because it avoids serious consequences in the environment of filling points, and in the environment of the farm in general. The destruction of packaging and its recycling prevents them to be reused, for example for transport of drinking water or getting lost in the environment.
This filling and washing point has an impermeable floor, retrieves all effluent for biological treatment (Phytobac® system), and is equipped with specialized measuring equipment.

All these issues boil down to two key points in the good management of farm inputs: training, and control.
I don't know any farmer who uses pesticides for fun.
The farms have now included in the monitoring routines of crops, all phytosanitary, meteorological and phenological (the stage of development of crop, which directly influences its sensitivity) observations, the presence of pests and diseases, the presence of helpful insects (beneficial organisms such as pollinators and predators). These are the main criteria that will allow us to take the decision to intervene or wait.

In developed countries, these points are more or less all implemented. However in developing countries, only exporters are really sensitized to it, by the demands of their customers. In these countries, there is still much progress to do in the management of pesticides.

It is clear that pesticides are potentially dangerous.

But there are two very different phases to be distinguished:

-       Handling of pesticides on the farm, during which the pesticide arrives concentrate to be diluted, so is handled in its dangerous phase. In this phase, the risk comes from the concentration of the product. This is the dose effect, in the same way that an excess of alcohol, coffee or drugs is dangerous for health.
-       The presence of possible residues on food, for which each pesticide has been very thoroughly studied, prior to the authorization of use. This work allows to conclude that risks that pesticides pose to consumer health are extremely low, if not nonexistent. To hold otherwise, as some don't hesitate to do, it's just to say that competent authorities knowingly poison the population. An extremely grave charge, and divested of any scientific foundation.

But it is clear that a good use of pesticides is a key factor for efficiency and sustainability.

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