Biopesticides: From Innovation to Registration in Europe / Serie #1

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Introduction:

Before being placed on the market, a phytosanitory product follows different stages, whether it is conventional or biopesticide. In the latter case, some specificities are to be taken into account. Staphyt regulatory experts, Amélie Grimaldi and Geoffroy Moulin, are explaining in this article the different steps and challenges of the biopesticides registration in Europe. 

This article will be available in 2 parts. Here is the 1st part.

Biopesticides are a contraction of ″ biological and pesticides″. In the European Union, they have been defined technically as a form of plant protection product based on micro-organisms or natural products (DG ENV. 18); they therefore contain antimicrobial properties of plant extracts and constituents, pheromones, etc. In France, biocontrol is defined as the ″ set of preventive and curative plant protection methods against crop enemies that are based on the natural processes at work in ecosystems ″.

While for the Rural Code and Marine Fisheries (L. 253-6), biocontrol products are ″ agents and products using natural mechanisms in the framework for integrated management of crop enemies.″

Mode of action, a first step for the marketing authorization

Case of micro-organisms and their metabolites

It is necessary to understand whether the micro-organism or secondary metabolites is responsible for the plant protection effects. In case the micro-organism is directly antagonistic to crop enemies, through spatial competition for example, it is relevant to build a dossier focused on this micro-organism and the risk assessment that it inherently constitutes. The dossier will therefore focus on the ability of the micro-organism to settle on the treated plot and its future in the environment will be one of the key points made in the note. In the case where efficiency operates only via secondary metabolites (molecules that perform non-essential functions of the organism and generally participate in the interaction between the organism and its biotic and abiotic environment) produced by the microorganism, the main problem consists in verifying that the viable microorganism actually produces the metabolite(s) in situ. Otherwise, a paradigm shift must be performed, focusing only on the metabolite or metabolites of interest. There is an intermediate case: when the substance of interest is present in the double cell membrane of the micro-organism, the quantity of the substance in the field is related to the quantity of cells applied and the viability of the micro-organism is not essential to the efficiency of the product.

Case of botanical extracts or microbial lysates

Two choices are available to the developer in the case of botanical extracts or microbial lysates. They can choose to identify precisely the substance causing the effect and try to purify it. The developer thus finds themselves in the situation of seeking approval of an isolated chemical substance. In the event that the purified substance does not present the full effect observed with the extract, it is more agronomically interesting to think about pursuing the approval of a UVCB (Unknown or Variable composition, Complex reaction products or Biological materials). Agronomy gains where ease of analysis loses as presented below in this article.

Other rids of reading to consider

Beyond the elements mentioned, ensuring the most relevant demonstration of efficacy requires identifying whether the substance has a preventive or curative activity in certain cases and if a plant defense stimulation (PDS) is involved. This is an additional point not to be overlooked. Laboratory work is strongly recommended in this case in order to go to the field with the most precise knowledge possible. Regarding PDS, knowledge of the elicited metabolic pathway (salicylic acid pathway or jasmonic acid for example) is necessary to anticipate the effect.

Passing controlled field tests

Once in the field, the main challenge is to find the mechanisms identified in the laboratory and verify whether these induce a greater effect than the intrinsic variability of the test plots. This part is never simple; going through tests on plants under controlled conditions can help the transfer of experience.

Practical value, incorporation into a treatment program

Experience has shown that biopesticides are often insufficiently effective to represent a single solution to a phytosanitary problem. Even if they have this efficacy, it has been demonstrated since the 1950s-60s via the theory of integrated protection that sustainable phytosanitary control is a strategy that combines multiple means of management in order to durably counteract the mechanisms of resistance of crop enemies. This is all the more important concerning chemical mediators which rarely provide complete control applied alone, and it is essential that beyond its intrinsic effectiveness, a review is carried out during the preparation of the substance approval dossier on the most relevant position in a control program (beginning, middle, end of the program, alternation with other control methods). For the majority of biopesticides, the most important part is demonstrating their practical value rather than intrinsic effectiveness. All this work is also a preliminary to the identification of the most relevant market positioning. Biopesticides require greater technical skill and attention to application detail than conventional plant protection products. Among the factors impacting efficacy, the following can be noted without being exhaustive; the choice of the volume of water applied, the choice of nozzles, the verification of the temperature on the ground and in the air, as well as the hygrometry during the application and in the hours following it. In some cases, the pH and water hardness can have an impact. The type of formulation can also have an effect on the rate of release of the substance and its preservation over time. Sometimes, ultraviolet light can degrade the micro-organism or the substance before they can reach their target. If moderate efficacy of the product is anticipated, it must be applied in an optimal situation to its best expression, for example on varieties with moderate or low sensitivity to crop enemies.

To be able to extrapolate the results obtained on a specific crop enemy to other organisms, it is necessary to evaluate the specificity of the solution. Cryptogamic diseases are not caused by the same microbial agents and this may have an effect on the expected effectiveness of the product. Similarly, differences in size, metabolism, and cuticles of different orders of insects can lead to relatively variable efficacy results.

Here we come to a paradox of biopesticides. Only those with zero to low environmental or human harms emerge from development tunnel testing. For those judged low risk, the regulations accept a demonstration of efficacy based on a smaller data package than a conventional product (PP 1/296_1 standard). Thus, the number of efficacy tests required in a file is less than for a substance or product presenting a greater risk. This goes against the technical and practical requirements: low-risk products generally require more precision when positioning them in a protection program and when using them, and they require more experimentation to identify the optimal conditions for effectiveness. There is a difficult balance to master between minimal information to be provided and optimization of knowledge.

Serie #2 of this article will be in AgroPages magazine Market Insight published in November, 2022.

For more information or any support in your biologicals products development, please contact Staphyt team: contact@staphyt.com   

www.staphyt.com 

This article was initially published in the magazine 2022 Biologicals Special.