The role of efficacy data for placing a plant protection product on the market

Eurofins' Senior Regulatory Expert, Eduardo Vidal Izquierdo, has worked for more than 10 years as an efficacy expert in the crop protection business. On several occasions, he has witnessed instances where specific uses of a plant protection product (PPP) were not approved by authorities due to missing or insufficient efficacy data packages. Here, he addresses some important questions…

Eduardo, does the efficacy of a PPP always have to be demonstrated?

The proof of the efficacy of PPPs intended for registration is mandatory criteria in Europe! The European Regulation (EC) No 1107/2009 and Directive 91/414/EEC demands demonstration of the active substance as a formulated product being sufficiently effective for at least one representative use for the approval of the active substance. Requirements for registration of PPPs are much more demanding with the need to demonstrate the performance of the PPPs in terms of direct efficacy on the target pest for each use for which authorization is sought.

So in Europe a full dataset testing the effectiveness is necessary for each crop-pest combination that is intended to be claimed on the label?

Generally, yes! For major use under unprotected conditions, about 10 fully supportive efficacy trials are required, while about 3 are needed for minor uses according to European and Mediterranean Plant Protection Organization (EPPO) guideline PP 1/226 (3). This number of trials is needed per area of similar conditions. However, it might be possible to use those data to extrapolate to other uses resulting in a reduced data package or even no data needed for these additional uses, following the extrapolation tables for minor uses of EPPO.

Are there any other possibilities to claim for a use without specific efficacy data?

Sometimes, it is possible to reduce the number of efficacy trials necessary to demonstrate the effectiveness for a certain use. Next to minor uses, this is possible for low risk-products or bridging approaches in the event of formulation changes for example, cases where there is a large amount of data available for the same product with different uses or similar products containing the same active substance, where there is little variation in climatic conditions or where it is according to specific national requirements. Many different parameters have to be taken into account, for that reason a good knowledge of the legislation is essential to obtain all the uses that you want on the label, without any unexpected surprises.

In addition to the demonstration of the direct efficacy against the target pest, is further data needed to complete the efficacy part for the submission of a PPP?

I like this question, because maybe this is not a well-known point.

The Biological Assessment Dossier, which is submitted to prove the efficacy of a PPP is mainly divided in two parts. In the first section, the efficacy of the product against the different weed/pest/disease targets of the product in the claimed crops has to be demonstrated. This is the well-known part. In the second part, different risk assessments are performed for the crops, plant products (yield), transformation process, succeeding and adjacent crops, beneficial and other non-target organisms to be sure that the application of the PPP is totally safe.

Of course, in order to perform these evaluations different trials should be conducted (crop safety, winemaking, brewing, taint-test, succeeding crops trials etc.). The need for these trials could change depending of the characteristics of the PPP and the label claimed. Parameters that have to be taken into account are the use (insecticide/herbicide/fungicide/growth regulator), mode of action (contact, systemic, translaminar etc.,), nature of the product (chemical, micro-organism, biological extract etc.,), target crops (cereals, vegetables, top fruits, olives, citrus etc.,), and the situation of the crop (field, greenhouse). For that reason, to know the legislation at EU level and know the need in each circumstance is crucial to obtain the desired results.

Does efficacy also have to be proven for other agricultural products not regulated by Regulation (EC) No. 1107/2009?

Within the new Regulation (EU) No. 2019/1009 laying down rules on the making available on the market of EU fertilizing products that came into force 16 July 2022, biostimulants are defined as a product function category. Apart from all other product categories covered by this regulation, such as fertilizers, liming material, soil improvers, growing media, and inhibitors, the efficacy of a biostimulant has to be demonstrated before it is allowed to be placed on the market. By definition, a biostimulant is not directly effective against a target pest, but can improve tolerance to abiotic stress, nutrient use efficiency, quality traits and/or availability of confined nutrients in the soil or rhizosphere. Those positive effects have to be proven with trials as indicated in the provisional Technical Specification (TS) of the European Committee for Standardization (CEN) CEN/TS 17700 series, Plant biostimulants – Claims (the European standard (EN) is currently in the enquiry period and is expected to be published in April 2024).

Do you have a take-home message?

Take care to fully address all sections of a dossier for plant protection products and biostimulants.

A complete risk assessment to ensure that active substances or formulated products do not have any harmful effect on human and animal health or any unacceptable effects on the environment for any of the uses intended for registration is required.

Don’t forget to demonstrate that the PPP is sufficiently effective against the relevant major target organism(s) in major crops, while at the same time, it is not significantly damaging the crops, or causing unacceptable adverse effects on plant products, transformation products, succeeding and adjacent crops, beneficial and other non-target organisms.

For every additional use that you intend to register, check if it is possible to fully extrapolate this from the existing data package. If not, an adequate efficacy data package (including adverse effects) has to be conducted, otherwise this use may not be approved even though the safe use has been demonstrated in the other sections of a submission. Same advice applies for biostimulants. Without the proving that the product induces the positive effects on the crop claimed on the label, it will not be possible to place the product on the market under the European fertilizer regulation.

If you have any questions on this article, please reach out to Eduardo Vidal Izquierdo