Ecological Pest Management (EPM) is an approach to increasing the strengths of natural systems to reinforce the natural processes of pest regulation and improve agricultural production. Also know as Integrated Pest Management (IPM), this practice can be “defined as the use of multiple tactics in a compatible manner to maintain pest populations at levels below those causing economic injury while providing protection against hazards to humans, animals, plants and the environment. IPM is thus ecologically-based pest management that makes full use of natural and cultural processes and methods, including host resistance and biological control. IPM emphasises the growth of a healthy crop with the least possible disruption of agro-ecosystems, thereby encouraging natural pest control mechanisms. Chemical pesticides are used only where and when these natural methods fail to keep pests below damaging levels” (Frison et al, 1998; 10).
The basis of this natural method of controlling pests is the biodiversity of the agroecological system. This is because the greater the diversity of natural enemy species, the lower the density of the pest population, and as diversity of natural enemy species decreases, pest population increases (Pesticide Action Network North America 2009).
The key components of an EPM approach are:
Crop Management: Selecting appropriate crops for local climate and soil conditions. Practices include:
Selection of pest-resistant, local, native varieties and well adapted cultivars
Use of legume-based crop rotations to increase soil nitrate availability thereby improving soil fertility and favourable conditions for robust plants that better face pests and diseases
Use of cover crops, such as green manure to reduce weed infestation, disease and pest attacks
Integration of intercropping and agro-forestry systems
- Use of crop spacing, intercropping and pruning to create conditions unfavourable to the pests.
Soil Management: maintaining soil nutrition and pH levels to provide the best possible chemical, physical, and biological soil habitat for crops. Practices include:
Building a healthy soil structure according to the soil requirements of the different plants (such as deep/shallow soil levels or different mineral contents)
Using longer crop rotations to enhance soil microbial populations and break disease, insect and weed cycles
Applying organic manures to help maintain balanced pH and nutrient levels. Adding earthworm castings, colloidal minerals, and soil inoculants will supplement this. Microbes in the compost will improve water absorption and air exchange
Soil nutrients can be reactivated by alleviating soil compaction
Reducing soil disturbance (tillage) – undisturbed soil with sufficient supply of organic matter provides a good habitat for soil fauna
Keeping soil covered with crop residue or living plants.
Pest Management: using beneficial organisms that behave as parasitoids and predators. Practices include:
Releasing beneficial insects and providing them with a suitable habitat
Managing plant density and structure so as to deter diseases
Cultivating for weed control based on knowledge of the critical competition period
Managing field boundaries and in-field habitats to attract beneficial insects, and trap or confuse insect pests.
IPM strategies can exist at various levels of integration. Note that integration at all four levels are not common (Frison et al, 1998; 11):
Control of a single pest on a particular crop
Control of several pests on the same crop
Several crops (and non-crop species) within a single production unit (farm)
Several farms in a region (area-wide pest management).
These practices, if well implemented, result in systems that are:
Self-regulating, maintaining populations of pests within acceptable boundaries
Self-sufficient, with minimal need for ‘reactive’ interventions
Resistant to stresses such as drought, soil compaction, pest invasions
- Capable of recuperating from stresses.
Contribution to climate change adaptation
Worldwide public attention has been focused on the importance of EPM since the United Nations Conference on Environment and Development held in Rio de Janeiro in June 1992. Agenda 21, the blueprint for action prepared by the conference, recognised pesticide pollution as a major threat to human health and the environment worldwide and identified IPM as a key element in sustainable agricultural development (Frison et al, 1998; 9).
EPM is a biotechnology belonging to the denominated ‘clean’ technologies which combines the life cycle of crops, insects and implicated fungi, with natural external inputs (i.e. bio-pesticides) that allows a better guarantee of good harvesting even in difficult conditions of pests and diseases that emerge with the temperature and water level changes (increase of relative atmospheric humidity and runoff) typical of climate change. Thus, it is a biotechnology for facing uncertainty caused by climate change.
EPM contributes to climate change adaptation by providing a healthy and balanced ecosystem in which the vulnerability of plants to pests and diseases is decreased (LEISA, 2007). By promoting a diversified farming system, the practice of EPM builds farmers’ resilience to potential risks posed by climate change, such as damage to crop yields caused by newly emerging pests and diseases.
With the EPM approach, farmers can avoid the costs of pesticides as well as the fuel, equipment and labour used to apply them. A 22-year trial comparing conventional and organic corn/soybean systems found that organic farming approaches for these crops use an average of 30 per cent less fossil energy (Pimentel et al, 2005). Although this can cause a slight drop in productive performance, the risk of losing an entire crop is reduced dramatically.
There are also reports that production levels have increased when there has been a reduction in the use of pesticides (Pesticide Action Network North America 2009). This is the case when there are specific controllers for a determined pest, for example, in West Africa the introduction of the wasp has been a spectacular control of the slug of cassava, thus saving the staple food crop for millions of Africans (FAO, 1996a).
There are very strong pests for which the ‘biological controller’ has not yet been identified (i.e. an insect that destroys it). When these pests emerge it is common for producers to turn to pesticides. EPM is not easy to implement and requires substantial knowledge and monitoring for the combined components of the system to produce success. Perhaps the biggest drawback to the EPM approach is that biological control is not a ‘quick fix’. In most cases, biological controllers will take several years to successfully establish a population and begin making a significant contribution. In addition, no single biological controller works in every situation. A controller that works well in one soil type, for example, may not work at all in another soil type. In the long run, more than one type of biological controller may have to be used to achieve uniform control across a variety of different situations and land types.
A national-scale IPM programme in Nicaragua implemented by CATIE in collaboration with seventy local service providers (such as NGOs, producer organisations, technical service providers, government extension agents), trained over 300 extension agents. These extension agents in turn trained over 8000 farmers but probably reached at least 15,000 farmers through collaborators applying the techniques to farmer groups not directly attended by the programme. Farmers’ pesticide use declined by between 30 to 70 per cent, but incidence of the major pests was reduced, and crop yields slightly increased. The combined cost of the training programme was about US$ 6.6 million over five years, but was considered to have generated a net benefit of approximate US$ 1.8 million due to reduced costs of production and increased yields (Guharay et al, 2005).
Knowledge and Monitoring Requirements
Knowledge is required on (i) pests and their natural enemies, (ii) effective and economic means of producing natural enemies, (iii) interactions between different means of pest control. Information on the various technological options that may be used to deal with pests and diseases is also required for the implementation of this technology. Multidisciplinary training on EPM for farmers, researchers and extension workers can help support transition to an EPM system. Early warning systems that allows for information on the population behaviour of insects, fungi and bacteria that could become plagues due to climatic variables (for example, a temperature increase) are also a useful tool for EPM implementation and monitoring.
Structures that enable farmers to organise themselves so as to jointly implement the proposed solutions are also required. Collective action can increase the successful development and implementation of EPM. Growers’ cooperation can help reduce the costs of EPM implementation. In addition, better linkages between research and extension, more extension services and private consultants, and improved monitoring can all contribute to better coordination and feedback, increasing the viability and impacts of the process.
Strong efforts in the area of communication with farmers are required so that they appreciate the benefits of applying this approach. Communication should be primarily focused on showing the range of advantages of this technology in comparison with other available options (such as longer-term sustainability and no environmental damage). Public sector agencies, such as ministries of environment, should lead on these initiatives.
Major constraints to the development and adoption of EPM programmes fall into four categories:
Technical: lack of studies and complexity of EPM
Economic: competing simplicity and apparent efficacy of chemicals; lower prices for EPM-produced goods (cosmetic damage); high cost of selective pesticides; lack of fiscal policy that favours EPM over pesticide use; high perceived risk if spraying is not carried out; failure to consider long-term advantages). A major obstacle to the implementation of this technology is that farmers generally prefer commercial pesticides because they are easier to apply and manage
Institutional (poor linkages between research and extension; lack of extension services, monitoring services, private consultants)
Educational (lack of understanding of EPM by farmers/extension agents, lack of EPM specialists) (Frison et al, 1998; 16-17).
EPM is complex and for farmers to understand and adopt EPM strategies they frequently have to change their whole pest control philosophy (Frison et al, 1998; 21). There is also a common misconception that pesticides are essential for high yields.
In agricultural production systems where the environment is relatively free of polluting elements (such as pesticides), and pests and diseases are becoming progressively more aggressive, conditions for EPM development are better. This is because there is no need to ‘clean’ the environment first in order to conduct research into which biological controllers are required. When EPM is used, farmers can benefit from the opportunity to sell their goods as healthy organic products that can fetch a higher market price.
FAO (2006) Breed diversity in dryland ecosystems. Information Document 9, Fourth Session of the Intergovernmental Technical Working Group on Animal Genetic Resources for Food and Agriculture. Rome. 2006
Frison E. A., C.S. Gold, E. B. Karamura, R. A. Sikora (1998) Mobilizing IPM for sustainable banana production in Africa Proceedings of a workshop on banana IPM held in Nelspruit, South Africa — 23-28 November 1998, INIBAP, 1998
Guharay F., J. Haggar, and C. Staver (2005) Final report of results and impacts 1998-2004 of regional program on ecologically based participatory implementation of integrated pest management and coffee agroforestry in Nicaragua and Central America to Norwegian Ministry of Foreign Affairs, CATIE, Nicaragua 130 pp
Pesticide Action Network North America (2009) La agroecología aporta un conjunto de soluciones para las crisis y presiones ambientales que enfrenta la agricultura en el siglo. In Agroecología y Desarrollo Sostenible, Conclusiones de la Evaluación Internacional de las Ciencias y Tecnologías Agrícolas para el Desarrollo, dirigida por la ONU
Pimentel, D., P. Hepperly, J. Hanson, D. Douds, and R. Seidel (2005) Environmental, Energetic, and Economic Comparisons of Organic and Conventional Farming Systems, Bioscience Vol. 55 No. 7. 2005
Clements, R., J. Haggar, A. Quezada, and J. Torres (2011). Technologies for Climate Change Adaptation – Agriculture Sector. X. Zhu (Ed.). UNEP Risø Centre, Roskilde, 2011, available at http://tech-action.org/