Integrated Pest (and Disease) Management

As the continuing rise in global population increases the pressure on food production to meet demand, many of the widely used tools to protect crops from damage are losing efficacy or being phased out due to negative environmental and health consequences. To understand how Integrated Pest (and Disease) Management (IPM) differs from current conventional crop protection it must first be placed in the context of mainstream agricultural practice, and the issues it seeks to address outlined:

Crop losses to pests, diseases and weeds

Losses of crop yield resulting from pests, pathogens and weeds, both in terms of quantity and quality, are among the most important pressures on global food and plant based-commodity production. Over the last 40 years, in many agricultural areas, diverse ecosystems have given way to simplified agro-ecosystems with increased vulnerability to pests, diseases and weeds (Oerke, 2006). Estimates of potential losses from damage by pests, diseases and weed competition vary with crop type and agricultural area, but on average, weeds result in the greatest potential loss (34 %), with an average of potential loss of 18 % to pests and 16 % to pathogens (Oerke, 2006). Reduction of the impact of pests, pathogens and weeds has largely been achieved through increases in the use of synthetic pesticides.

Current control strategies

Control of pests and pathogens in conventional agriculture is primarily achieved through the application of synthetic pesticides, with weed control managed through a combination of mechanical and chemical methods. The amount of pesticides used globally increased up to 20-fold from 1960 to 2004 (Oerke, 2006). The use of pesticides is not uniform across agricultural regions; The EU, while only possessing 8 % of the world’s agricultural land, accounts for around 31% of the global pesticide market (Eurostat, 2007). This reliance on synthetic pesticides to protect against yield losses incurs both an economic penalty to the grower due to the cost of treatments, an environmental cost due to off-target effects of the pesticides (including negative effects on beneficial insects such as pollinators) and a human health cost, especially to growers in developing countries where safety standards are lower (Thundiyil et al., 2008). Recent EU reviews of pesticides have led to the creation of policies resulting in the withdrawal of over 60 % of active ingredients from the European market. There are to be further reductions in the number of pesticides available in the EU as a result of revisions to 91/414/EEC, and tightening of Maximum Residue Limits combined new Sustainable Use of Pesticides and Water Framework Directives will further limit the use of the remaining pesticides, particularly herbicides (Birch et al., 2011).

Pressures on conventional agriculture

There are many pressures that are reducing the efficacy of conventional strategies to protect crops from pests, pathogens and weeds:

Pesticide Resistance - An over reliance on synthetic pesticides to control pests, pathogens and weeds is, in many cases, leading to resistance in many key pest species. For example, aphid species with multiple insecticide resistance, fungicide resistance in Phyophthora infestans (causal agent of late blight in potato) and the emergence of herbicide resistant weeds.

Breakdown of genetic resistance - One of the major non-pesticide control strategies for reducing potential damage from pests and pathogens is the breeding of genetic resistance into varieties. The emergence of strains of pathogens that can overcome resistance has led to the breakdown of genetic resistance that has been bred into crops, and this has been attributed to increasing pest pressure, which has been linked to climate change in some cases.

Loss of habitat for beneficials - The move away from smaller farm areas to larger broad-acre agriculture has seen the loss of semi-natural habitats that are habitats for natural enemies to crop pests (that provide biological control services within crops) and for pollinators as well. The use of pesticides, changing climate, loss of habitat and introduction of invasive species are among the list of multiple stressors that, on a landscape scale, are acting in additive and synergistic ways to have negative impacts on organisms that are beneficial to agriculture.

Climate change - Increases in climatic instability and alteration of potential ranges of pests, pathogens and weeds will make the behaviours of these groups and their resulting impacts more difficult to predict. With less certainly of where, when and to what extent a crop will be impacted by a given pest, pathogen or weed, mitigation of their potential impact will become more difficult, resulting in greater losses (Gregory et al., 2009). This uncertainly could negatively impact crop yields and food security.

Pesticide withdrawal - See 'Current Control Strategies' section (above) for information on the impending withdrawal of over 60 % of active ingredients from the European market.

Integrated Pest Management

Integrated Pest Management (IPM) is a sustainable approach to managing pests by combining biological, cultural and chemical tools in a way that minimises economic, environmental and health risks. This is best achieved by combining a range of compatible IPM tools (e.g. use of pest resistant crop varieties, biocontrol, biopesticides, precision monitoring of key regional pests, using action thresholds before applying selective pest reduction treatments). The IPM toolbox needs to be fine-tuned according to regional cropping systems and varying pest pressures. The practical application of IPM does not exclude careful use of approved and selective pesticides if and when needed (e.g. if pest thresholds are exceeded and other IPM tools are either not available or too slow acting to protect the crop at a particular time in the cropping season). The overall aim is to reduce pest populations below damaging levels whilst minimising adverse effects on beneficial organisms (e.g. pollinators and natural enemies of pests) in the agro-ecosystem.

Integrated Pest Management in the European Union

Framework Directive 2009/128/EC “…establishes a framework to achieve a sustainable use of pesticides by reducing the risks and impacts of pesticide use on human health and the environment and promoting the use of integrated pest management and of alternative approaches or techniques such as non-chemical alternatives to  pesticides.” To achieve this, the directive requires the application of eight principles of IPM, which have been summarised by Barzman et al. (2015) with the following summary titles:

Principle 1 – Measures for prevention and/or suppression of harmful organisms (pests)

Principle 2 – Tools for monitoring pests

Principle 3 – Threshold values of pest numbers on a crop as the basis for decision making

Principle 4 – Non-chemical methods to be preferred

Principle 5 – Target-specificity and minimisation of side-effects on beneficial organisms such as pollinators and biocontrol agents

Principle 6 – Reduction of pesticide use to necessary levels

Principle 7 – Application of anti-resistance strategies for permitted pesticides

Principle 8 – Records, monitoring, documentation and check of success of pest suppression

A video that summerises IPM has been created by the Linking Environement and Farming (LEAF) organisation, which is based on the eight principles outlined above; that researchers at the James Hutton Institute helped to develop.

At the James Hutton Institute, our research covers all of these eight principles to varying degrees, with a focus on major crops of Scotland; cereals, potatoes and soft fruit.

Citations

Oerke E-C. 2006. Crop losses to pests. Journal of Agricultural Science 144, 31–45.

Gregory PJ, Johnson SN, Newton AC, Ingram JSI. 2009. Integrating pests and pathogens into the climate change/food security debate. Journal of Experimental Botany 60, 2827–2838.

Eurostat. 2007. The use of plant protection products in the European Union. Data 1992–2003. Downloadable web source: http://epp.eurostat.ec.europa.eu/cache/ITY_OFFPUB/KS-76-06-669/EN/KS-76-06-669-EN.PDF.

Birch ANE, Begg GS, Squire GR. 2011. How agro-ecological research helps to address food security issues under new IPM and pesticide reduction policies for global crop production systems.  Journal of Experimental Botany 62, 3251-3261.

Barzman M, Barberi P, Birch ANE, Boonekamp P, Dachbrodt-Saaydeh S, Graf B, Hommel B, Jensen JE, Kiss J, Kudsk P, Lamichhane JR, Messean A, Moonen AC, Ratnadass A, Ricci P, Sarah JL, Sattin M (2015). Eight principles of integrated pest management. Agronomy for Sustainable Development 35(4): 1199-1215.

Thundiyil J G, Stober J, Besbelli N, Pronczuk J (2008). Acute pesticide poisoning: a proposed classification tool. Bulletin of the World Health Organization 86(3): 205-209.