Microbial Biostimulants: What the Regulation Says

Microbial biostimulants are live beneficial microorganisms (usually bacteria or fungi) that are applied to seeds, soil, or plants to stimulate plant growth and improve plant health, without being classic fertilizers or pesticides. Here's a brief overview of the current regulatory status within the EU for microbial biostimulants – and importantly, what this means for you as a farmer.

What the FPR actually allows today

According to the EU Fertilising Products Regulation FPR (Regulation (EU) 2019/1009), only four groups of live microorganisms may be used in CE-marked microbial plant biostimulants:

• Azotobacter spp.

• Azospirillum spp.

• Rhizobium spp.

• arbuscular mycorrhizal fungi (AMF)

If you see a CE mark on a microbial product labelled as a PFC 6(A) microbial plant biostimulant, the technical file must show the microorganism is one of the four allowed groups listed above. If the organism listed is e.g. Bacillus subtilis, then the CE claim would be inconsistent with the FPR and the product would not be legally a CE microbial biostimulant. Regulators and notified bodies check conformity.

What about products that contain other microbes (e.g., Bacillus, Pseudomonas, Trichoderma)?

The FPR is optional harmonisation: it does not ban “non-harmonised” fertilisers. Products that are not CE-marked can still be sold under national fertiliser laws and general free-movement/mutual-recognition rules.

This means that many microbial products that contain organisms other than the four groups listed in the FPR (Azotobacter, Azospirillum, Rhizobium, AMF) are still sold in the EU, but they cannot be placed on the market as CE-marked “microbial plant biostimulants” under the Fertilising Products Regulation. Instead they must follow a different legal pathway. Manufacturers therefore typically adopt one of these routes:

• Market under a different legal framework — for example as a microbial plant protection product (PPP) when pesticidal/antagonist claims are made (this requires EU or national PPP approval and safety data).

• Market as a national (non-CE) fertiliser/soil amendment or “biofertiliser” under Member State rules where national markets still accept such products (national rules vary and some Member States maintain their own registration systems for microbial inoculants).

• Sell as a non-live microbial derivative (e.g., fermentation metabolites, dead/lysed cells, enzymes, LCOs) and therefore rely on other CMCs or non-microbe biostimulant classifications under FPR. The FPR text and guidance distinguish live microbes from dead/empty-cell material and derivatives.

Industry groups (e.g. EBIC) have been actively lobbying to expand the scope of CMC-7 because many commonly used beneficial taxa (e.g., Bacillus, Pseudomonas, Trichoderma, some actinomycetes) have strong agronomic evidence.

What does this mean for a farmer?

From a farmer’s point of view, the difference between CE-marked and other microbial biostimulants boils down to how tightly the product is regulated, how widely it can be sold, and what kind of microbes you can actually get your hands on.

Very briefly:

• CE-marked microbial biostimulants give you: more consistent safety and labelling, easier acceptance in audits and cross-border contexts, but currently a narrower range of microbes and sometimes higher compliance-driven cost.

• Non-CE-marked microbial biostimulants give you: more microbial diversity and innovation and often strong local products, but with less harmonised oversight, more homework for you on labels and data, and a bit more regulatory uncertainty if you operate or source across borders.