NATURAL
VS SYNTHETIC - PHEROMONES
In
the late 1980s, I was a young fruit production advisor in the South-East of
France for a specialized technical group, the GRCETA of Basse Durance.
After
the group was contacted by an Australian company, I had the opportunity to
participate in the first trials to test on a large scale the protection against
oriental fruit moth (one of the most dangerous pests in this area) by
pheromones, with the technique called sexual confusion. This Australian company
was trying to test its diffuser and its pheromone under conditions of high
pressure of the pest. Logically, it wanted to do it in the region
internationally known as the most problematic one.
You
have to know that at that time, the oriental fruit moth turned into a real
nightmare for peach growers in the region. The pest populations were extremely
high. There were some problems with the loss of efficiency of the usual
insecticides, forcing farmers to do frequent pesticide interventions with
insufficient levels of efficiency, hence both technical and economic problems.
At the time, there was virtually no mention of the environmental consequences,
but from the current perspective, it is scary...
The
fact is that this Australian company came up with this innovative technique,
plunging us into an abyss of reflection, and doubt.
Imagine
thirty years ago, the proposal to solve a critical problem of insects without
insecticides. For us, advisers, in whom the farmers of the group sometimes
blindly confided to help them to solve their problems, it seemed insane. We
were very motivated by the innovation, but sincerely, given the seriousness of
the situation in some areas, we were also very suspicious.
The
experimental zone was chosen in a concrete area of Provence which was in such
a critical situation with regard to the oriental fruit moth that some farmers
began to consider a conversion of crops when faced with the impossibility of
controlling the damage.
After
a whole season of experiments, the farmers' surprise at the results was
pleasing to see. Without being wonderful, they were superior, without
insecticide, to the enhanced program that they needed to implement, and that
included more than 15 chemical sprayings.
After
two years of testing, the conclusion was that to resolve a much degraded situation,
it was necessary to go through a first phase that combines chemical protection
with sexual confusion, enough time to reduce the level of infestation (1 to 2
years). From this moment, confusion alone is enough to avoid the damage.
At
that time, as a technician participating in the tests, I always had a number of
diffusers in my car in order to be able to replace one, or to complete a dose
in a difficult place. The consequence?
I
was pursued every day, both in the car and outside, by a wild horde of oriental
fruit moth males, persuaded that I was the princess of their dreams...
Pheromones
are natural substances, emitted by living organisms to transmit information to
their conspecifics.
Their
role is well known in most animals, and in some plants.
These
are generally volatile compounds, produced by exocrine glands. Unlike hormones
designed to be used internally by the body, pheromones are produced to be
released outside the body to transmit a message or signal to individuals of the
same species. Their role in the sexual reproduction of insects is well known
and has been the subject of numerous studies.
It
is thanks to sexual pheromones that, for example, Lepidoptera (butterflies) male
are able to locate females, allowing them to mate and continuity of the
species.
Each
insect has its own "aromatic bouquet" in order to attract individuals
only from its own species.
In
addition, pheromones have different types of roles such as sexual attraction,
alarm, aggregation, territoriality, and exist in almost all animals, even in
humans. Bees use them to indicate flowering areas, ants to mark their paths,
dogs and cats to mark their territory, humans in situations of fear or sexual
desire for example.
They
can also be found in products designed to calm or repel dogs or cats, or even
to make you irresistible in a night club.
The
principle of the technique of sexual confusion is thus the following one.
The
pheromone contained in the diffuser is the same as that emitted by the oriental
fruit moth female so that the male is able to find it, and thus can mate. The
diffuser is made of a porous plastic which allows a progressive diffusion of
the pheromone for several weeks.
In
nature, a female emits the pheromone that is carried by the air. The male
receives this olfactory message through a specific receiver and follows the
trail until it finds the female.
The
technique of sexual confusion consists in distributing a large number of
diffusers in the cultivated plots. In this way, the points of emission are so
numerous that the male is practically unable of finding the female.
The
mating is disturbed, the reproduction does not take place, so the insect is no
longer a problem for the farmer.
Traditional protection involves
killing existing insect pests to prevent them from breeding and causing crop
damage.
Sexual confusion means preventing
insect pests from being able to reproduce. They are therefore not present in
the crop and don't cause damage.
This
is a profound change in the concept of crop protection. It is a technique of
prevention of the damage.
So
we have a technique that works well, and that avoids the application of
chemicals on the crop. It should be noted that pheromones are used in agriculture
in at least 3 different techniques:
Sexual confusion, which consists in
diffusing a very large quantity per hectare, so as to disturb the males in
their system of approximation of the females, drastically reducing the
possibilities of mating and therefore of reproduction. Pest populations decline
"naturally", and consequently, damage to crops.
Monitoring trapping, which consists of placing
a few pheromone traps on the farm, in order to capture individuals and to
monitor populations (beginning of flights, peaks of flights, time of hatching
and risks). This technique, the first historically speaking, to use pheromones,
makes possible to locate with a great accuracy the exact moment of intervention
with insecticides, synthetic or natural. That was one of the foundations of
Integrated Production.
Mass trapping, which consists of placing
traps with a large quantity of pheromones, in a reduced number per hectare, in
order to capture a large number of individuals, thus reducing the pest
population without applying pesticides. This technique is much used with food
attractants, more than with pheromones.
The
technique of sexual confusion has developed considerably and is now used to
protect crops, especially in vineyards and orchards, against mainly
lepidoptera, diptera, hymenoptera and beetles.
Obviously,
the technique was very quickly authorized in organic farming. It is logical, a
technique that allows effective protection without using pesticides, neither
synthetic nor even natural, deserves attention.
But in fact, these pheromones,
freed in large quantities and permanently, where do they come from?
No,
there are no swarms of worker pressing on the abdomen of billions of female
butterflies to draw a microdrop of pheromone each time.
It
is chemistry, pure and hard.
These
pheromones are synthetic, precise copies of natural ones, derived from
chemistry, naughty chemistry.
They
are then enclosed in plastic diffusers, also derived from the naughty
chemistry.
But
can these synthetic chemicals, released into the air from crops, reach the
food?
Without
any doubt. My personal experience of the 1980s has amply demonstrated that
these pheromones are deposited on everything around them. Otherwise, I would
not have been pursued by all these confused and excited males!
Their
effect is fleeting, it is true, but the reality is there.
So, would organic agriculture allow
large-scale use of synthetic chemicals that come into direct and permanent
contact with food?
Well yes, absolutely.
Picture:
https://endhairloss.eu/wp-content/uYSDGUysdgp87/2014/04/Organic-products-to-stop-hair-loss.png
However,
the gravity of the case must be put into perspective. These are synthetic
products, yes, but they are exact copies of natural molecules.
As
in the case of azadirachtin, right?
For
azadirachtin (and you will soon see that this is not a unique case), the copy
of the natural product is refused because it is synthetic and therefore
incompatible with the ideology of the organic, despite all the technical and
environmental advantages in relation to the extraction and use of the original
natural substance.
Except
that this prohibition of principle, questionable in itself, but consistent with
organic ideology, is not always applied. There are situations where a breach of
the rules is possible.
Note
that the consumer of organic products, ultimately the engine of the system, is
not aware of these changes in the rules of the game.
The
information it receives remains the same. No chemistry in organic production.
But
what would he say, the organic consumer, convinced that there is no chemistry
in the organic production, and that he really
takes care of his health and the planet, if he learns that they lie to him
every day, that he is jobbed by those same people in whom it has placed its
confidence?
Is this a double standard?
It
must be recognized that agriculture is not easy, and that crops must be well
protected from diseases and pests, even in the case of organic products. And if
there is no organic solution, we will find one, almost organic. We should not
lose the market.
This is not sexual confusion, it is
intellectual confusion.
Amazing blogpost which is very useful and informative thanks for sharing this.
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