Field Efficacy Testing for Biocides (PT18 and PT19)
Dr. Andrea Drago from Entostudio in Italy, collaborator in the working group for PT19, spoke at the Dublin Biocides Symposium in March 2023 on the topic of field testing for the efficacy evaluation of biocides for PT18 and PT19. The discussion focused on the publication of the new 5.0 version of the ECHA guidance which includes more detailed and defined methodologies to assess PT18 and PT19, as well as new concepts introduced in the latest guideline for PT19.
One of the significant changes for PT19 is that there is no longer differentiation between professional and non-professional uses, except for stored goods – attacking insects and mites, where laboratory tests have been substituted by simulated-use or field tests. Simulated-use tests, performed in closed spaces like a cage or a room, are now required for products intended for consumers or non-professional users, while professional users of PT19 require field tests in open spaces.
The latest guideline for PT19 also introduces new concepts, the most relevant being the evaluation of mortality. A scientific peer-reviewed literature search should be carried out to prove that a repellent product for the intended uses does not cause any adverse effect to the target organism. If insufficient data is generated by the literature search or lethal effects are reported, testing is required. These tests are performed in the lab since it is almost impossible to observe this in the field. The test is considered valid only if the mortality of the treated group does not exceed 10% of the mortality of the control group.
Andrea continued the presentation by discussing several other key points that should be considered for PT19, including the location of field tests, methods of application and particularities for parasite repellents applied directly to animals. He also provided interesting details related to field tests in mosquitoes, the most relevant organism for PT19. Tests for mosquito repellents must be performed in one of two mosquito species, Culex or Aedes. The species Anopheles may be added if efficacy against tropical mosquitoes needs to be demonstrated. The field test involves using volunteers in open fields or in a small gazebo or greenhouse. Field tests are also required for wasps, ants, and cockroaches.
Andrea ended by highlighting that for PT19, the choice of tests will depend on the intended use, while for PT18, the test setting will define the results. All tests for both product types require a strong scientific basis.
A copy of the slides are available here: https://kerona.ie/product/dublin-biocides-symposium-2021-speakers-presentations/
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