Pesticides in cannabis: risks, regulations and alternatives

A pesticide is any substance used to prevent, eliminate or control harmful organisms - insects, fungi, weeds, rodents, bacteria - that threaten the health or yield of cultivated plants. In the context of cannabis, pesticides cover a broad spectrum: insecticides (against pests such as red spiders and thrips), fungicides (against oidium and botrytis) and biopesticides (substances of natural origin).

Cannabis is a particularly sensitive crop when it comes to pesticides, for one simple reason: it is consumed by inhalation. Pesticide residues that do not pose a problem in a fruit or vegetable become potentially dangerous when they are concentrated and heated at high temperature in a seal, a spray or a concentrate.

Why pesticides are particularly problematic on cannabis

During combustion or vaporization, residual pesticides present on flowers are thermally transformed. Certain compounds that are relatively non-toxic in their raw state generate pyrolysis by-products clearly more harmful when burned - the most documented case being myclobutanil (a common fungicide), which produces hydrogen cyanide on combustion.

In the concentrates as the BHO or the distillate, the fat-soluble pesticides present in the raw material concentrate in the final extract, sometimes to levels several times higher than those measured in the original flower. This is why residue standards for concentrates are generally stricter than for flowers on the legal market.

The main categories of pesticides used on cannabis

Regulations and residue testing

On the legal markets (USA, Canada, Germany), producers are required to have their products tested for a panel of residual pesticides before marketing. The results are published in the certificate of analysis (COA). Each state or country sets its own maximum residue limits (MRLs) per pesticide and per type of product (flower, concentrate, edible).

Visit France and Europe, As yet, there are no specific regulations governing the use of pesticides in CBD flowers. General agricultural rules apply to industrial hemp, but the CBD market remains in a regulatory limbo. Serious growers nevertheless have their batches voluntarily tested and display COAs.

On illegal markets, the presence of unauthorized pesticides or pesticides used outside their conditions of use is frequent. Without mandatory testing, consumers have no way of knowing.

Alternatives to chemical pesticides: IPM

The integrated pest management (IPM) is the approach that minimizes or eliminates the use of chemical pesticides by combining prevention, biological control and reasoned chemical intervention as a last resort. This is the standard adopted by professional growers on legal markets:

• Natural predators Predatory mites against red spiders, Amblyseius against thrips
• Biopesticides : Bacillus thuringiensis (Bt), Beauveria bassiana, neem oil
• Physical barriers insect netting, quarantine of incoming goods
• Natural fungicides potassium bicarbonate, micronized sulfur (with pre-harvest interval)

How to check your cannabis for pesticides

In a legal market, the certificate of analysis of the batch purchased must include a panel of pesticide tests carried out by an ISO 17025-accredited laboratory. Results are expressed in µg/g (micrograms per gram) or ppb (parts per billion), together with the relevant MRLs.

For CBD consumers in France, asking for the COA is the only way to check. A producer who refuses to provide it is a red flag.