Skip to main content

Rationale and background

UK farmers and growers are facing a considerable challenge to adopt more environmentally acceptable methods of crop production and protection while maintaining food quality, productivity and profitability. Herbivorous insects, plant diseases, and weeds are major threats to food production and are becoming increasingly difficult to control by conventional methods as a result of the withdrawal of chemical pesticides following UK and EU reviews, coupled with pressure from retailers to reduce chemical pesticide inputs in the food chain.  However, there are good opportunities to reduce chemical inputs using Integrated Pest Management (IPM) based on biological control agents.  In particular, microbial control agents, based on naturally occurring fungi, bacteria, viruses or nematodes, can offer realistic alternatives to chemical pesticides when used as part of an IPM strategy (Tanada &  Kaya, 1993).  This project is concerned with microbial bio-insecticides for the control of insect pests, since it is an area in which the project consortium has considerable expertise, but similar microbial agents exist for the control of plant diseases (e.g. bio-fungicides) and weeds (bio-herbicides).  Collectively these agents are known as microbial biopesticides and their use accords with Defra’s Science and Innovation Strategy for 2003-6, which has a specific objective to develop ‘alternative plant protection technologies, such as novel bio-control methods … so as to reduce reliance on conventional pesticides’.  Microbial biopesticides are usually applied inundatively, in a way that is analogous to chemical insecticides, but many of them also exhibit desirable biologically-based properties (specificity, reproductive potential, low impact on non target organisms, compatibility with other natural enemies, limited toxic residue) (Dent, 2000).  In addition, they offer the prospect of a number of broad social advantages for the rural economy: ‘Because of its flexibility of scale, the biopesticide business can have the desirable properties of exploiting local biodiversity, creating employment and wealth in agricultural communities, and reducing the need for import of pest control from distant centres of production.’  (Waage, 1997, p.14).

Despite their perceived advantages, there has been a poor uptake of microbial biopesticides in the UK due to socio-economic factors centred around regulation.  The safety and efficacy of fungal, bacterial and viral biopesticides are regulated in the UK by the Pesticides Safety Directorate.  The regulatory system was developed according to a chemical pesticides model, aspects of which act as barriers to biopesticide commercialisation (Advisory Committee on Pesticides, 2003). Some of the obstacles are market related.  Much of the development of microbial biopesticides has been initiated in the public sector and taken up by SMEs, for whom the registration fee and the associated data package are proving prohibitive (Coghlan, 203).  However, it is our view that the economies of scale arguments are well understood and they will not provide a major focus of this project.  Instead, the aim of this proposal is to improve understanding of the environmental and regulatory sustainability of biopesticide development and utilisation, using a fungus-based microbial bio-insecticide as a model system. The use of the same regulatory framework as chemical insecticides inevitably focuses attention on the costs of biopesticides rather than their potential benefits.  Under the chemical regulatory model, specific and short-term goals can prevail over long-term aims of environmental protection and social benefits.  This is an unintended consequence, resulting from inbuilt features of regulatory systems which have a bureaucratic tendency for policy instruments to be considered in isolation from their wider effects.  Understanding the limitations of the chemical model is essential if regulatory barriers to biopesticide uptake are to be overcome.  At the same time, the environmental sustainability of deploying biopesticides in agricultural systems is unclear, and the role of micro-organisms is little studied, even though many are naturally widespread in agroecosystems (Chandler, 1997).  Because microbial biopesticides tend to be host specific, their use offers benefits in terms of minimal direct effects on non target organisms, but there could be unwanted indirect effects (Pearson & Callaway, 2003), especially on naturally occurring microorganisms occupying the same niche.  On the other hand, local adaptation of natural microbial agents, which is already known to be important to generating biodiversity in host-pathogen systems (Dybdahl and Storfer, 2003), could prevent biopesticide genotypes from persisting and expressing desirable biological effects.  Investigating the behaviour of biopesticides in the environment is particularly pertinent since the chemical pesticide model encourages them to be used as components of ‘technological’ IPM which relies on frequent inundative applications for pest control.  This contrasts with the theoretically more sustainable ‘whole systems’ approach, which utilises biopesticides and other agents to back up naturally occurring pathogens and other organisms which resist pest outbreaks (Lewis et al., 1997). 

A key challenge for this project, which is particularly relevant to RELU, is that it might be possible to demonstrate that: (a) inundative applications of biopesticides do not pose unacceptable environmental risks and bring many benefits, but (b) there may be an insufficiently well defined political arena in which to develop an appropriate system of regulation.  In other words, there may be a mismatch between the scientific possibilities and the regulatory mechanisms necessary to realise them. 


sem root aphid