Nicotine

Nicotine is the precursor to neonicotinoids.

The use of tobacco as a pesticide has been known for a long time. It was the French agronomist Jean-Baptiste de La Quintinie who discovered the biocidal properties of nicotine extracted from the tobacco plant in 1690. Nicotine acts as a powerful neurotoxin against insects. Dried tobacco leaves were also used in wardrobes to protect clothing from moths.

Nicotine mimics a neurotransmitter in the insect nervous system by binding to nicotinic acetylcholine receptors, leading to paralysis and death. The pests most susceptible to nicotine are aphids, caterpillars, mites, and whiteflies.

At the beginning of the 20th century, nicotine and nicotine sulfate were manufactured by agrochemical companies, notably from cigarette waste. At that time, nicotine sulfate was one of the most widely used insecticides for pest control.

Oxygen in the air, bacteria, and UV radiation rapidly degrade nicotine after it is applied. To counteract this drawback, chemists attempted to modify its chemical formula. In 1980, more stable derivatives of nicotine, called neonicotinoids, appeared. Nicotine was very quickly replaced by these safer and more selective synthetic insecticides.

Neonicotinoids are systemic insecticides, meaning they travel through the plant’s vessels to be distributed in the leaves and flowers (for this reason, it is strongly advised against using these insecticides during the flowering period).

The systemic action of nicotine and its synthetic derivatives provides long-lasting protection against pests. Depending on the chemical formula, these insecticides remain in the plant’s vascular system for varying lengths of time, but they eventually disappear before the plant products are consumed if very strict usage guidelines are followed. While some neonicotinoids are still authorized in Europe, in France, neonicotinoids have been banned in agriculture since 2018. Professionals have a few exemptions granted in 2026 (Duplomb II law) to combat certain persistent pests when effective alternatives are lacking (sugar beets, hazelnuts, certain fruit crops, etc.).

Nicotine and organic farming

The use of nicotine, often touted as more environmentally friendly, is frequently recommended in organic farming, even though this natural insecticide has the same undesirable effects as synthetic alternatives. Nicotine is not a targeted biocide and, due to its broad spectrum, this neurotoxin poisons both harmful and beneficial insects. Nicotine is even less selective and more toxic to beneficial organisms than some of its synthetic derivatives.

Nicotine-based insecticides are made from dried tobacco leaves. Most often, the tobacco leaves are chopped and soaked in water for a few days to create a natural spray. This infusion is then sprayed on the plants. A few drops of liquid Marseille soap are said to help the nicotine adhere to the leaves longer in case of rain.

Due to the high toxicity of nicotine infusions to humans, wearing protective equipment is essential. The rapid degradation of nicotine infusions necessitates frequent reapplication of treatments, which inevitably limits the purportedly less toxic effects on the environment and risks creating resistant pests, as has already been observed with neonicotinoids.

Warning: tobacco cultivation in France is highly regulated. Without authorization from an authorized government agency, growing tobacco for personal use is prohibited (check with your local Prefecture). There are websites where you can buy tobacco leaves, most often intended for rolling your own cigarettes, which is far removed from the principles of organic farming. Furthermore, tobacco leaf cuttings are considered manufactured products. The French General Tax Code specifically states that the sale and purchase of manufactured tobacco products remotely are prohibited in France.

Ultimately, let’s avoid complicating our lives with tobacco for both ecological and regulatory reasons, especially since biocontrol alternatives exist, such as physical protection (insect nets, etc.), the introduction of beneficial insects, etc.