There is an urgent need to make crop protection more sustainable and effective. In December 2008, we advised the European Parliament Committee on Agriculture and Rural Development on Integrated Pest Management and the future prospects for ‘alternative’ methods of pest control. Below is a summary of the report. You can see the full report at: https://www.europarl.europa.eu/RegData/etudes/note/join/2008/408962/IPOL-AGRI_NT(2008)408962_EN.pdf
Global agriculture is in a period of tremendous change. There is increasing tension between the need to produce food and protect other ecosystem services. Food production will need to increase significantly in the near future to feed an expanding human population, but this must be done without causing further harm to the planet. Pests (invertebrates, plant pathogens and weeds) are major constraints to agricultural production. There is an urgent requirement for systems of pest management with greater levels of sustainability. These must be capable of increasing or maintaining food productivity and have positive outcomes for environmental services.
The main pathway for achieving this is through Integrated Pest Management (IPM). IPM is a systems approach that combines a wide array of crop production practices with careful monitoring of pests and their natural enemies. IPM practices include resistant varieties, timing of planting, physical methods, cultivation, biological controls, and judicious use of pesticides to control pests. The aim of IPM is not pest eradication; rather it is the more realistic goal of reducing a pest population below its economic injury level. IPM does not rule out the use of synthetic chemical pesticides. Rather, pesticides are used when systematic monitoring indicates a need. Other forms of pest management are used to keep chemical interventions to a minimum.
IPM can play a significant role in making farming more environmentally, economically and socially sustainable: it can help to maintain biodiversity, reduce pollution, lower the build up of pesticide resistance, maintain the security of food supply, increase yields, and improve consumer confidence in the agri-food industry
Non-chemical control methods can make valuable contributions to crop protection. These include physical and cultural controls, natural compounds, biological control, plant breeding and other genetic methods. In some situations, a combination of methods may be able to replace synthetic pesticides, for example where a pest has developed pesticide resistance. But in most cases the most practical way forward is to use them with chemicals in a fully integrated programme.
Crop rotation is one of the oldest strategies for managing pests and is particularly useful for controlling pest species with limited dispersal ability and host range. Other physical and cultural control methods have a role to play in IPM strategies for one or sometimes several pests. Much research has been devoted to identifying ‘natural’ compounds for pest control and many have been used successfully for pest insect monitoring. There are fewer examples of compounds that have been used successfully for pest control and considerable research and development investment would be required to expand this portfolio.
Biological control can be a very successful part of IPM. Biocontrol agents tend to have a narrow activity spectrum. This is attractive from an environmental perspective but it also makes them niche market products, which can act as a barrier to their commercialisation. There are significant differences in the biological control strategies used in, and the amount of success obtained with, glasshouse vs. outdoor crops. More investment in research and development is needed, particularly for biocontrol in field crops.
Plant breeding, i.e. the growing of resistant varieties, is often promoted as an alternative to the use of pesticides. Although there has been some work to breed for resistance to invertebrate pests, the majority of effort has been directed at resistance to microbial plant pathogens. Many hundreds of pathogen resistance genes have been identified in crop species. However, no plant variety is resistant to all diseases and pests, and the choice of variety is always a balance between different traits. Moreover, most resistance is ephemeral due to the ability of pathogen populations to overcome it through natural selection. Host resistance must be used, therefore, as part of IPM in order to achieve durable crop resistance.
GM crops can provide economic and environmental benefits. However if the technology is not used according to IPM principles then sustainability gains may be lost. If there are large-scale effects from GM then they should become apparent in the 8 countries outside the EU that are now growing over 1 million ha of GM crops. The ethical issues surrounding GM are complex and there may be specific concerns for certain groups of people. Scientists can provide valuable knowledge about GM but policy making is the responsibility of Governments. Effective engagement between all members of the policy network is vital.
The uptake of IPM varies significantly depending on the type of crop grown. IPM is being used widely in glasshouse crops and some sophisticated systems have been developed. Some components of IPM are used in field vegetable crops including crop rotation, careful pest monitoring and resistant varieties when available. IPM strategies in orchard crops are largely based on not using sprays of broad spectrum pesticides to preserve natural enemies of the main pests. There is considerable scope for IPM in arable crops but it does not appear to be used widely. The majority of schemes are based on pest forecasting, monitoring and varietal resistance rather than on biological control.