How widespread is their use? Despite the extensive research and multiple advantages of microbial biopesticides, they only represent <1% of the global market for agricultural pesticide sales (Chandler et al, 2008). Of this figure, 90% of sales are from just one bacterium, Bacillus thuringiensis (Chandler et al, 2008). More than 200 products are registered for use in the United States, but only 60 are registered in the European Union, with just 5 available in the United Kingdom (Chandler et al, 2008). Why has there not been a higher uptake? Two reasons… MARKET FAILURE Microbial biopesticides are highly specific and therefore the market size is too small to recover the development and registration costs. REGULATORY FAILURE Regulation of crop protection products in Europe began in the 1960s after problems with pesticides were reported and non-governmental organisations (e.g. Greenpeace and Pesticide Action Network) changed public perceptions of pesticides (Ehlers, 2011). Specifications of products acceptable for release onto the market were drawn up by the European Pesticides Directive and based on guidance from agrochemical companies. Consequently the criteria focused primarily on efficacy. Regulation of biological control agents (BCAs) was therefore assessed based on criteria modelled on synthetic compounds. Prior to regulation, many BCAs were used and throughout their history of use no negative effects had been reported. Despite this however, use of many BCAs stopped as registration costs were not justified. Although the regulatory system seems to be counterproductive, a precautionary approach was enforced due to past failures to prevent environmental damage. The fungicide tolylfluanid for example was recently banned in the UK because after microbial degradation in the soil and entrance into water systems, ozone treatment converts it into the carcinogenic compound N-nitrosodimethylamine (NDMA) (Orosová et al, 2010). Recently, however, people have begun to realise the potential of BCAs for use in agriculture, horticulture and forestry and consequently the regulation and registration of microbial biopesticides has been reviewed. Regulation focuses more now on ecological impacts and the cost of registration has been reduced. In 2007 for example the cost of registering a biopesticide in the UK was £22,500 compared to £175,000 for registering a chemical pesticide (Chandler et al, 2008). Commercialisation of biological control products however is still largely down to small companies. Further change in regulation and registration therefore needs to occur to stop bias being granted towards chemicals. Despite these limitations, the market for microbial biopesticides is expanding. (Chandler et al, 2008)