Pesticides, warming: agriculture has found "its limits"

Whether to reduce pesticides or to combat the effects of global warming on plants, agronomic research "progresses" and "gives rise to a lot of hope", explains to AFP the President of INRA , Philippe Mauguin.

"The general approach of the National Institute of Agricultural Research", presented this week at the Agriculture Fair, "focuses on the diversity of resources within a single species" to explain how "crosses of wild varieties naturally resistant to certain diseases can genetically reinforce varieties currently used in agriculture or arboriculture," said Mauguin in an interview on Wednesday.

Because according to him, l French agriculture as it has existed since the Second World War "has found its limits".

After the war, "we had organized the choices of varietal selections with the aim of feeding the country, and we have multiplied yields by three in a few decades thanks to genetic selections, inputs and agrochemistry. "

" But we saw the limits of this system in the late 1990s, with case of water pollution, especially via the effects induced by a weed-killer, atrazine, which was finally banned in 2003 but which leaves long-lasting effects ", underlines Mr. Mauguin.

For several years, Agriculture has tried to correct the side effects of chemistry on the earth and the environment, with "reasoned" practices that limit the use of pesticides.

"But the answers were not fast enough, and we saw the limits of the plan + Ecophyto +", launched by President Sarkozy in the wake of the Grenelle Environment Forum, admits the one who was director of cabinet from the previous Minister of Agriculture Stéphane Le Foll: "a simple optimization of the use of phytosanitary products is not enough".

– Radical Change –

After stating that "farmers do not use pesticides for pleasure, but to protect their crops, "Mr. Mauguin stresses that the goal is to" change the entire agricultural production system in a radical way. "

" But it is not obvious ", recognizes -he.

He presented Tuesday the new agronomic approaches under study to Ministers Frédérique Roussel (research) and Nicolas Hulot (Ecological Transition).

The first is the increase of biocontrol, that is to say Neutralization of aggressors with their predators, usually insects. Trichogramma, for example, destroys corn borer, which attacks maize in particular

The second approach is to improve varietal selection in order to make seed varieties more resistant to diseases and thus limit the use of chemical pesticides.

INRA presents on its stand the first four vine stocks from its research, carrying genes resistant to powdery mildew and mildew, which will reduce by more than 70% the use of pesticides on the market. vine: Vidoc, Voltis, Floreal and Artaban

"In January, we included in the catalog of varieties these first four resistant grape varieties, two for red wines and two for white wines," says Mauguin. INRA is expected to release about twenty more in 2019.

This approach is developed for all species. "We accompany the seed companies for the first stage of propagation" and then they continue, explains Mr. Mauguin.

On some species the work is very long and frustrating. For lettuce, for example, "in 20 years, we have found about 30 resistant genes, but the aggressors still bypass, defend themselves and we must constantly seek new resistant genes."

On the disputed herbicide glyphosate, INRA estimates that it is able to offer alternatives "that can be complicated to set up" for 80% to 90% of use cases.

"We evaluated technical dead ends between 10% and 20%", essentially in the field of soil conservation agriculture, says Mauguin.

This type of agriculture is of great interest in the fight against global warming, since by removing plowing, it can store carbon in the soil. But it requires the use of a weed killer once a year to clean the soil before sowing, to allow the seeds to grow.