Pest Control with Microbial Biocides

Chemical pesticides have made major contributions to the fight against hunger and infectious diseases, but sometimes pose risks due to their side effects on the environment and human health. Biological agents might increasingly replace chemically active substances. The Federal Institute for Occupational Safety and Health (BAuA) is one of the organisations responsible for their assessment.

In the last century chemical pesticides helped to maximise harvests, prevent crop spoilage, and contain infectious diseases such as malaria and typhus. By the middle of the twentieth century, though, it had become clear these active substances were also causing undesirable damage to nature and human health, while pests were also becoming resistant to them.

This realisation had several consequences. Firstly, alternative active substances were sought that were just as effective, but had the smallest possible side effects. Secondly, restrictions and bans were imposed on harmful chemically active substances such as DDT. In recent years, above all, increasing numbers of biological agents have been developed, authorised, and put to use. These are micro-organisms or biological substances of natural origin and, in addition to their positive environmental attributes, are often highly target-specific in comparison to synthetic active substances.

Bacillus thuringiensis: a microbial biocide

One of the most frequently deployed biological agents is the bacterium Bacillus thuringiensis which is commonly found in soil. Thanks to its production of insecticidal proteins, it is of particular importance in the fight against malaria, the cultivation of agricultural crops, and efforts to control the oak processionary moth.

Assessment of microbial biocides

Regulation (EU) 528/2012 harmonises the assessment, authorisation, and restriction of biocides throughout the European Union, covering pesticides for use as disinfectants, preservatives, and antifouling and embalming products. In Germany, the coordination of these activities is incumbent upon the Federal Office for Chemicals (Bundesstelle für Chemikalien, BfC), which is based at the Federal Institute for Occupational Safety and Health (Bundesanstalt für Arbeitsschutz und Arbeitsmedizin, BAuA). Some plant protection products are very similar to biocides. The lead role in their assessment in Germany is taken by the Federal Institute for Risk Assessment (Bundesinstitut für Risikobewertung, BfR). Regulation (EC) 1107/2009 governs the authorisation of plant protection products in the EU.

The basis for the evaluation of these substances includes studies of their health risks, environmental compatibility, and efficacy. The current lists of active substances for biocides can be viewed on the website of the European Chemicals Agency, and those for crop protection products on websites of the European Union.

As active substances for pest control, biological agents differ in many respects from chemicals because they are able to multiply, adapt, and change. The microbiological and molecular-biological analytical techniques used to identify them and evaluate their purity, health risks, environmental persistence, and other characteristics also differ fundamentally from the methods used for chemical active substances. The same also applies to, among other things, DNA sequencing, growth conditions, and pathogenicity tests.

BAuA's unit 4.II.1 "Biological Agents in OSH", deals with the technical aspects of the European and national authorisation of biologically based biocides in collaboration with BAuA's unit 4.II.3 "Biocides Assessment OSH", and the Fedral Office for Chemicals.

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