The efficacy and tolerability of plant protection products is subject to a detailed examination in the approval procedure - in addition to the other assessment areas of ecotoxicology, environmental behaviour, residue behaviour and toxicology.
In principle, plant protection products can only be authorised if a corresponding effect has been demonstrated for the intended use. The efficiency to be achieved for a positive conclusion of the effectiveness evaluation is typically at the level of preparations already approved (for this application purpose). Under certain conditions listed below, lower efficiencies may also lead to a positive outcome of the evaluation procedure:
- Longer application window in culture than comparable preparations;
- Efficacy against several stages of development of the pathogen;
- less dependence of effectiveness on climatic factors;
- better compatibility with other plant protection measures;
- additional effect on other pathogens;
- less side effects on beneficial organisms or subsequent cultures;
- positive properties regarding active substance resistance and anti-resistance strategy.
For this reason, the indication supplement "to reduce infestation" has already been used in the evaluation of efficacy in case of need. In order to take account of new developments, in particular concerning plant protection products based on low-risk active substances, a third category "only partially effective" is now introduced. The indicative values with regard to the allocation to the respective categories are given in the following table. The percentages given may vary depending on the type of effect, the crop and the pathogen in question.
Reference values Efficiency in terms of efficacy
|Recommended value Efficiency||Restriction of the indication|
|over 80 %||None|
|60 % - 80 %||to reduce infestation|
|less than 60||only partially effective|
If the restriction "only conditionally effective" is applied, the following additional condition is imposed: The instructions for use must provide comprehensive information on the conditions of use under which the efficacy is to be expected.
If necessary, the approval will continue to refer to certain restrictions or conditions of use under Other requirements and information.
If a marketing authorisation is not based on an assessment of efficacy, as is usual for gap indications (Art. 51) and emergency marketing authorisations (Art. 53), the following requirement is generally imposed: Possible damage due to lack of effectiveness or damage to cultivated plants is the responsibility of the user. For these indication(s), the user must check the tolerability and efficacy under his specific operating conditions before use.