mercredi 15 juillet 2015

48- Plant protection -2- Reminder


Human memory has an extremely limited rear vision.

One proof of that is the current movement against vaccination.
Under what pretext do we want to go back on vaccines? Just because they have side effects? Under the pretext that the diseases against which they protect us are eradicated?
What it better, to tolerate the side effects of vaccines, or attend a resurgence of smallpox, polio or plague? Because it should not be forgotten that a side effect, for unpleasant it may be, is above all secondary. Do you know that on June 27th, 2015, a child died in Barcelona, ​​so in Europe, a modern city with huge health resources? And from what did he die, this poor child? From diphtheria. Yes, you read well, from diphtheria, a disease eradicated in Spain for 30 years. And you will ask, why the hell this child was not vaccinated? Well, because his parents are opposed to the principle of vaccination.
It is easy to say that vaccines are useless when (almost) everyone around is vaccinated and the diseases against which we are vaccinated have actually disappeared from our usual environment.
But we forget that vaccines fill a need. We forget that the world is large and that the diseases may still exist somewhere. Until the day when the drama occurs ...
A very sad story, don't you think?

The current situation of pesticides in industrialized countries is, at my opinion, comparable to that of vaccines in many ways. Indeed, why do we want to remove pesticides? Because too many people have a too short memory.
I am lucky, like most of my readers (as I see by the statistics of the blog), to live in a region, where living conditions are generally pleasant, with a quality health system, with virtually unlimited availability for all products needed for a comfortable life. On the other hand I observe that opponents to pesticides and to vaccines are mostly city dwellers, gentrified, comfortably free from hunger and epidemics. They have very easy access to clean water, they choose their food and like to vary is so much nicer!
They are opposed to pesticides from an ideological or philosophical point of view, while refusing to see that their use primarily responds to a need, and their ban could lead to serious problems. When ideology is blind ...
I also note that everyone is concerned about the future, which is very healthy, but also that everyone, which is very unhealthy, forget the past but also the present when it is distant. The problems of others affect us little when they are not close, or when we don't feel ourselves threatened. When ideology makes selfish ...

Some examples to refresh your memory.

The desert locust (Schistocerca gregaria). 
This is a large insect, important food source for some local populations. Yet, it all times assumed serious problems, and is still today a constant threat in Africa and Asia. The ancient sacred texts like the Bible or the Koran refer to it as a divine scourge. Under certain conditions the insect, usually solitary and quiet, becomes gregarious, it undergoes physiological alterations and its behavior changes completely. Huge swarms form in sub-Saharan Africa that move flying. The observed large swarms can cover up to 1,200 km2, bring to 80 million individuals per km2, and move up to 200 km per day. These swarms generally last several years (3 to 10 years depending on climatic conditions) destroying everything in their path, and producing toxic waste. Some swarms may sometimes fly till Spain and Russia. The 1989 swarm even managed to cross the Atlantic Ocean to reach the Caribbean islands. Since 1990 FAO has set up supervision service, monitoring weather conditions and locust populations, so as to intervene preventively, when conditions are favorable for the formation of swarms. The alert from 2003 to 2005, according to FAO data, affected 20 African countries, had a cost of $ 400 million in means of control and destroyed for a value of over $ 2.5 billion of crops, causing huge food insecurity throughout this fragile region. Pesticides, insecticides in this case, judiciously placed on the swarm creation places, at the right time, can prevent the formation of the flights, without eliminating the insect. Applied too late, swarms are already too powerful and treatments become ineffective, requiring considerably higher doses. We can thus, by abruptly reducing populations, give the insect back its solitary nature, and limit its damage. But the means to implement are complex and expensive. The threat is permanent.

Ergot fungus (Claviceps purpurea). 
It is a disease that can attack rye and many other grains, and produces a hallucinogenic toxin, from which was made the famous LSD. At low doses, it gives visions and unstable behavior, but in high doses, this toxin is deadly and produced frightening symptoms. In the Middle Ages, the disease was known under the name of Saint Anthony's Fire, or Ignis Sacer. There are, in the course of history, thousands of direct victims by poisoning, plus many local famines caused by the destruction of contaminated crops. The last reported cases date back to 1951 in France, and it is also a leader of the "Great Fear" in 1789. This would also be a cause of the Salem witch trials in North America at the end of the seventeenth century. Currently, the use of fungicides prevents its development, but the disease remains. The threat is permanent.

Late blight of potato (Phytophthora infestans). 
This is one of the most common diseases of potato. It is also a fungus. It is favored by warm and humid climates. Once implanted in an area, it is virtually impossible to eradicate. Currently, almost all the potato production areas in the world are infected. In the mid-nineteenth century it appeared in Ireland, where potato was the staple food par excellence. The devastation was enormous in fields, causing a terrible famine. This was the main trigger of the great Irish emigration to North America. Late blight of potato has been one of the main causes of food insecurity in European and American countries until the discovery of effective chemical fungicides. Indeed until then, production fluctuated with climatic conditions. Currently, inattentive producers still have serious problems, and some years are very difficult. The threat is permanent.

The great famines in History. 
When they were not caused by wars or political decisions (case of the "Great Leap Forward", launched in 1958 and which caused one of the most deadly famines in history of humanity), they were caused by climatic problems and their consequences on food production. I just told you about Ireland, but many cases are comparable in history, even if they rarely had such socio-political consequences. One can speak of the intense cold, hail, terrible droughts like repetitive ones of Sahel, and long rainy periods. These are the ones that interest me today. Because every prolonged rain period can cause serious disasters because of fungi and bacteria attacks. If farmers have no means to control them, they can lead to a serious lack of food. These famines, very real throughout the history of the world and responsible of millions of victims, are now avoided in most cases by the use of fungicides and bacteriostatic products, in short, through the use of pesticides.

They don't really have a place here, since they don't have an "historical existence" in so far as they have been identified in recent decades. However, given their potential frequency and the badly known risk they represent, it is highly likely that they are responsible for many health problems in History. What is it? They are toxic substances produced by fungi or molds. The fungi that produce them are quite common on many crops (maize, wheat, peanut, grape, apple, fig ...) or in processed products such as bread, wine or beer. This is especially the case of fungus genera Aspergillus, Fusarium, Penicillium and Alternaria. There are others, among which we find Claviceps purpurea, the causative agent of ergot, which I just mentioned. The risks and severity varies with the toxin, but can be associated certain irritations and allergies, immune system declines, and even some cancers. Much research are underway to determine the precise extent of risks. Fungicides are used to prevent the development of the fungi, and consequently the associated risks of these contaminations. The progress of research confirms their implication in many health problems. The risk is misjudged, but the threat is permanent.

I think these examples are enough for you to understand that the use of pesticides does not initially respond to productivity logic. It responds primarily to a health and food security logic.

Caution, don't make me say what I don't want to say. I don't defend the indiscriminate use of hazardous products. I defend the usefulness of pesticides, I support the urgent need for further research to improve what exists, and I argue that populism and clientelism of many people, trying too much to remove pesticides under voluntarily exaggerated pretexts, threatens the food security and food independence. I also defend the need to maintain existing pesticides as they have no effective alternatives. This is why in a previous article (45- save the bees I told you that I was opposed to ban neonicotinoids. I prefer to support tougher conditions of use and more controls, until farmers have alternatives.

Rome was not built in a day. Similarly, as good French, I am proud of the French Revolution, and of belonging to the cradle of modern democracy. But democracy has not been made on 14 July, 1789. How many round trips (republic, empire, monarchy, other revolutions, wars) were necessary? How many millions of deaths were necessary to be able to enjoy, today, a level of equality and democracy ever experienced so far?
Crop protection was maintained in a stable situation of powerlessness for millennia. Then the Industrial Revolution was accompanied by the Agricultural Revolution, allowing the introduction of mechanization, chemical and scientific knowledge. Chemistry has probably taken a disproportionate share in agricultural production. But it took time to realize it.
After the excesses, usually unintended, of the early times of agrochemicals, we approach an equilibrium, with innovative technologies, with chemistry present but not intrusive (albeit some think so) and daily advancing scientific knowledge.

Let us learn to be patient. This is the biggest flaw of our modern civilization of the XXIst century. We want everything right away. But what is possible in certain activities, is not possible in others.

We gained food security. It seems won to us. But no, it is not won. We still have to fight for it. We have to gain it day after day, through the efforts of farmers, scientists and food industry, which change the world little by little. There are still almost 800 million people suffering hunger in the world. This is unacceptable, yet it is every year a little less bad. This proves that food security is not a given.

Let's not do things too quickly. One day perhaps we will be able to dispense with most existing chemicals. Why? Because they will have been replaced by other solutions and other less problematic products, chemicals or non-chemical, and because biotechnologies and scientific knowledge allow it. But we are not there yet.
I only hope, with this article, to make you understand that chemistry and pesticides are beneficial. There are risks and disadvantages? Everyone knows this. But chemistry brings us great things every day, which we do not even realize.

Let things evolve. If you want them to go faster, push for it. But don't demand drastic measures without knowing the consequences.

Our current achievements are still fragile, and excessive decisions could lead us to flashbacks with serious consequences.

Aucun commentaire:

Enregistrer un commentaire