Useless, when time will come to weed the yard and the driveways are gravel, to seek to obtain glyphosate. You won’t find them. Same thing when the mildew will to your tomatoes or the aphids on your roses: fungicides and insecticides, chemicals used up to now to stem parasites of plants have also disappeared from the shelves of garden centres.

Since January 1, in effect, the law Labbé, passed in 2014, prohibits the sale, use, and even the detention by the gardeners of synthetic pesticides. Only the products of biocontrol (natural chemicals, sex pheromones…), those at low risk (herbal preparations), and those whose use is allowed in organic agriculture, such as the famous bordeaux mixture, can now be used in private gardens.

also read: VIDEO – How to control weeds without glyphosate?

Although toxic to soil and aquatic environments, the bordeaux mixture is still authorised against late blight of tomato. afp

“This is a revolution in the practice of gardening, a new state of mind that it is necessary to provide the best support to enable people who were not prepared to initiate this shift in the best conditions,” explains Jean-Marc Muller, vice-president of the national Society of horticulture of France (SNHF), and a member of the steering committee of the official website Gardening otherwise. In the clear, “the goal is not simply to replace synthetic pesticides with a natural alternative but to rely more on observation and the prevention of free-riding on its eradication.”

Now, it is mainly the upstream that action should be taken. In sowing or planting to a date favourable to plants adapted to the soils and climate of its region ; selecting, when available, varieties that are genetically tolerant to bio-aggressors ; alternating crops, promoting biodiversity, and thus the predators (blue tits, hedgehogs, ladybirds…) that will help to keep pests below an acceptable threshold, etc

read also: Tomatoes, salads: sow varieties that are resistant to diseases

The larvae of ladybugs are big eaters of aphids. Vincent Albouy/SNHF

These prerequisites will not, however, respond to all situations, nor with all hazards, in particular climatic conditions. In some cases, the gardener will need to continue to highlight its spray, when the subtle balance that it has attempted to establish will be broken by the emergence of one brutal parasite, as seen during wet summers where diseases (downy mildew, powdery mildew) can cause a heavy toll.

fortunately, some bios have already made their proof. Bacillus thuringiensis, or Bt, is a good example. This bacterium secretes a protein insecticide that provides effective control against many insect pests, starting with the dreaded borer boxwood. By attracting the males to pheromone traps, mating disruption is another green way to control the populations of insect pests, such as codling moth or worm of the apple tree. Ladybugs, as you can get in the trade, but also the larvae of lacewings or flower flies, are great eaters of aphids. Not to mention the black soap and the vegetable oils that destroy these sap-sucking plugging their holes breathing abdominal, or insecticides based on pyrethrum, a natural insecticide extracted from a species of chrysanthemum.

Bicarbonate of soda herbicides bios are not very effective against perennial plants, such as thistle. 65046093/khalesi – Fotolia

The range is unfortunately much more limited vis-à-vis diseases of fungal origin. Only the sulphur, to control powdery mildew, and the bordeaux mixture (downy mildew of the vine, the potato and the tomato) come out of the batch but this last is not free of blame on the environmental plan: accumulation of copper in soil, toxicity to aquatic organisms… As for the baking soda, milk and plant-based preparations, such as suspension of nettle, horsetail, or comfrey, very in vogue at the moment, their effectiveness has never been proven experimentally.

In terms of weeding, those who refuse – and one understands them – to wield the hoe have as an alternative to mulching, boiling water (rather than throw it in the sink…), burners, gas-fired or electric, the désherbeurs manuals (practical to pull out the dandelions in the lawn) or herbicides, organic white vinegar, or acid pélargonique. Disadvantage: if these drugs work in a few hours by burning the foliage, they have not, unlike systemic herbicides such as glyphosate, no lasting effects on perennial plants such as buckwheat, sorrel, thistles, buttercups trailing or woody plants (buddléias, ailantes…) that can be used to repel sec. additionally, they cost five to thirty times more expensive…

Importantly, this approach of gardening, certainly more ecological but also more random, require, to succeed, more knowledge, technical expertise and availability than before. At a time when the time becomes paradoxically a scarce commodity, it will be interesting to see how gardeners deal with this dramatic shift.


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