Plant protection products based on biopesticidal active substances often require a different approach to efficacy than conventional chemical products. Biopesticides, even more so than chemical products, require detailed understanding of their mode-of-action and the effect they can have on the target pest or disease, and which conditions are required for them to reach an optimal level of effectiveness.

For developers, this creates both a regulatory challenge and an opportunity. Efficacy data requirements for products based on low-risk active substances are less extensive than those for conventional chemical plant protection products. Though the data package may be reduced and reasoned cases may be presented in lieu of actual data, it does not mean that producing an efficacy dossier for a biopesticide is simple. Taking advantage of reduced requirements and the possibility to rely on argumentation depends on understanding the mode-of-action of the product and the conditions required for it to work, as well as having a clear picture of the claims being sought and the evidence genuinely needed to support those claims.

The revised EPPO Standard PP 1/296(2), approved in 2025, provides guidance on the minimum efficacy data requirements for plant protection products based on low-risk substances.

Biopesticide Does Not Automatically Mean Low-Risk

One important distinction is that biopesticide and low-risk plant protection product are not interchangeable regulatory terms.

From a regulatory point of view, many biopesticidal active substances may be regarded as low risk. The criteria for low-risk active substances are defined in Regulation (EC) No 1107/2009, as well as in Commission Regulations (EU) 2017/1432 of 7 August 2017 and (EU) 2022/1438 of 31 August 2022, amending Regulation (EC) No 1107/2009.

A biological, naturally derived or microbial active substance does not automatically qualify as low-risk. The relevant regulatory criteria still need to be satisfied.

There is also an important distinction between the status of an active substance and the status of the finished plant protection product.

A plant protection product is regarded as a low-risk product when it contains only low-risk active substances and does not require specific mitigation measures following a risk assessment.

Low-Risk Biopesticide vs Conventional Product Efficacy

EPPO guideline PP 1/296(2) offers guidance on the minimum efficacy data requirements for low-risk products. Next to this, EPPO guideline PP 1/276(1) offers guidance on the evaluation of microbial plant protection products.

EPPO guideline PP 1/296(2) describes that the required efficacy data is less extensive than what is required for conventional chemical products. The number of trials may be reduced, dose justification is simpler and a moderate level of effectiveness may be acceptable.

The efficacy package does not necessarily need to rely exclusively on conventional field trials either. Depending on the product and intended uses, laboratory or small-scale studies and scientific publications may contribute useful evidence relating to mode-of-action, target susceptibility, dose response and the environmental conditions affecting performance.

Does a Low-Risk Product Need to Perform As Well As Conventional Chemistry?

Not necessarily.

PP 1/296(2) recognises that products based on low-risk substances may provide a worthwhile plant protection benefit without necessarily achieving the same level of control as a conventional chemical reference product.

A moderate level of effectiveness can potentially be acceptable where the product provides a genuine benefit in its intended use. This may be particularly relevant where the product forms part of an Integrated Pest Management (IPM) programme or helps maintain pest or disease pressure at an acceptable level.

Whether a product provides a sufficiently useful and reliable benefit for the claimed uses should be analysed case-by-case.

Applying conventional expectations to a product with a very different mode-of-action or intended role may result in trials that fail to demonstrate its genuine value.

Importance of Mode-of-Action for Biopesticide Efficacy

All-in-all, developing a biopesticide efficacy dossier asks for a tailor-made approach that considers the mode-of-action of the product, properties of the target pests and crops and situations in which you want to apply.

Mode-of-action can influence the trial methodology, appropriate dose justification, environmental conditions required for performance and the opportunities available for extrapolation.

For some products, factors such as temperature, humidity, leaf or soil moisture, crop growth stage and pest pressure can materially influence efficacy. Understanding those factors becomes important both when generating regulatory evidence and when defining how the product should ultimately be used.

When dealing with a new active substance, or a new use of an existing active substance, the first step is to gather information on its potential effectiveness. Scientific literature may offer information on which targets could be controlled, and at which rates. In a next stage, preliminary testing will offer vital information on the possibilities and limitations of your product, which can also (partly) be used to build your efficacy dossier. Acquiring this information before starting GEP registration trials will substantially reduce the risk of disappointing results and consequently loss of investment.

Reduced Data Requirement Requires Clear Strategy

In many cases, the reduced data requirement does not simply allow you to conduct fewer trials. Often, a low-risk product would offer a less consistent effect and would therefore require more data to conclusively demonstrate its benefit.

The potential to reduce the data package lies in designing an efficacy programme that makes full use of the available knowledge on the active and subsequent extrapolation. With a well thought through efficacy programme, each trial and each piece of supporting evidence contributes as much as possible towards the intended registrations.

For this reason, before starting GEP efficacy testing on a practical scale, it is useful to have a clear view of:

• the product's mode-of-action and intended claims.
• target crops, pests, diseases or weeds.
• opportunities to use existing evidence or extrapolation.
• effective dose rate.
• conditions that may affect product performance.
• the countries in which authorisation will be sought and the major/minor status crops and targets in those countries.
• the product's intended place within practical crop protection or IPM programmes.

A well-designed programme may reduce unnecessary work, make better use of existing evidence and identify opportunities for the same data to contribute towards a wider range of intended uses.

Planning Biopesticide Efficacy Early

Blue Frog Scientific, and sister company, Linge Agroconsultancy, can support developers in interpreting efficacy requirements, developing an appropriate regulatory strategy and identifying opportunities to make better use of existing and newly generated data.

Getting those decisions right early can help ensure that efficacy investment supports the registrations and claims the business ultimately wants to achieve.

If you have any queries relating to biopesticides or are looking for a consultancy to support you through the registration process of a biopesticidal product, call or email and speak directly with one of our biopesticide regulatory specialists.