Plant protection based on botanical active substances
On 20 March 2014, the EU published a Guidance Document on Botanical Active Substances Used in Plant Protection Products where the approach of the plant extract it is as follows:
Botanical active substances differ from synthesized chemicals in their origin. Synthesized chemicals are produced by chemical reactions whereas botanical active substances are obtained by processing material of biological origin.
To defend themselves against herbivores (including insects) and pathogens, plants produce a variety of components (also called 'secondary plant compounds') including volatiles such as various alcohols, terpenes and aromatic compounds. These secondary plant compounds can enable plants to resist pathogens, deter insects or other herbivores from feeding, can have non-toxic or direct toxic effects on pests or they may be involved in recruiting predators and parasitoids in response to feeding damage. They may also be used by the plants to attract pollinators or they may be involved in interplant communication. As these properties have been known and observed for a very long time, it is a logical progression that some of these compounds have been identified as candidates for crop protection use.
The composition of a botanical active substance depends on the material of biological origin, the manufacturing process(es) and may depend on further processing and purification. Therefore, botanical active substances may have a larger variation in the qualitative and quantitative composition than synthesized chemicals.
The production of substances of biological origin is influenced by the geographical areas and climatic conditions (e.g. time of sunshine, rain, soil etc.) and differs each year. Therefore, the nature and concentrations of substances vary naturally and affect the quantitative and qualitative composition of the botanical active substance.
In addition, the way of processing the botanical active substance has an impact on the composition of the extracted material which varies depending on the technique applied (e.g. cold-pressing, water-steam-distillation, extraction with (organic) solvents or a combination of several steps) often resulting in a complex mixture of several components. As a result, different botanical active substance of the same biological origin could have different compositions. Therefore, certain physical parameters related to the processing method could be regarded as important for characterising a botanical active substance
This is shows that in most jurisdictions, it is acknowledged that for some of the data requirements for plant extracts a different approach may be taken if adequately justified to facilitate the approval of these kinds of substances and the authorisation of plant protection products containing botanical active substances.