Integrated Pest Management
Integrated Pest Management
Integrated pest management is the integration of several strategies to manage pest species in an agricultural system. It encourages a move away from a sole reliance on pesticides or insecticides (but does not exclude their use), to combine a variety of biological, ecological and cultural methods for more holistic control of pests. These practices aim to control pest species through the use of resistant cultivars of plants and by encouraging a build-up of natural enemy and beneficial populations in order to keep pest populations at a level below economically damaging thresholds, thus mimising the use of agrochemicals
The correct identification of insect pest species is essential for successful IPM. Similarly, a sound understanding of the interactive biology of the insects and plants within a cropping system is necessary.
IPM requires regular monitoring of crops for both pest and beneficial insects. Information obtained from monitoring is used to assist decisions regarding when to spray (based on economic thresholds) rather than prophylactic (preventative), injudicious application of insecticides. IPM practices utilise selective insecticides and those with shorter residual periods which will have a lesser impact on non-target species. Particularly in the early stages, the identification, monitoring and decision making within an IPM framework requires support from appropriately trained agronomists, entomologists and researchers.
Conversion to IPM practices should be viewed as a long-term process and ideally, the monitoring of insect populations would begin one to two years before implementing IPM.
Area Wide Management
Outbreaks of pest species rarely occur on an isolated crop or farm, and similarly the beneficial insects that keep populations in check do not follow such narrow geographic boundaries. Area Wide Management (AWM) aims to apply IPM across an entire pest population within a defined geographic region. Consequently, a farmer managing pests through IPM would gain the benefits of neighboring properties also promoting populations of beneficial insects. Area Wide Management will require significant forward planning, long-term commitments to such practices by growers within that defined region and a sound understanding of the biology and ecology of pest populations, as well as that of the broader agroecosystem in which they reside.
Why move to IPM?
Integrated Pest Management tactics have in part been developed in response to the overreliance and failure of chemical solutions to provide long-term solutions to pest problems:
The use of broad spectrum insecticides kills natural enemies of pest species as well as more generalist beneficial species. This can result in increases in pest problems because of the loss of natural controls in a cropping system.
Chemical insecticides provide a temporary respite from pest populations and in the majority of cases need to be applied recurrently, putting in place a spiral of dependence on ecologically disruptive chemicals.
Many pests develop resistance to chemicals over time. This can lead to a further spiral of increased pesticide use in order to kill increasingly resistant insect pests. When combined with the destruction of populations of beneficials, the consequences for pest control can be devastating in the longer term
Furthermore, the use of broad spectrum insecticides has the potential to lead to the development of secondary pests and "flaring" in other non-targeted pest species such as aphids, whitefly and mites, again this is due to the disruption of populations of beneficial insects.
Chemicals may be environmentally and ecologically disruptive. For example, high rates of pesticide use may kill insects and other organisms that might otherwise feed on the pest species. There is a loss of concomitant ecosystem services that such species provide such as pollination generalist predation.
Finally, pesticides and their breakdown products enter the soil and waterways and as such may have a detrimental effect on humans, non-target organisms and the broader environment.
Why people might resist changing to IPM:
IPM is often perceived as a complex system with a great diversity of insects. However this diversity is a favourable thing as the majority of insects within an IPM system will be beneficial. With the help of trained entomologists, growers can quickly become familiar with what are pests and what are beneficial. Many of these insects will be providing other ecosystem services such as pollination, nutrient cycling and food web interactions as mentioned above.
Broad spectrum insecticides are seen as a relatively cheap option in the short-term. However, due to the necessity of reapplication on a regular basis, the costs associated with the development of resistance in target species and environmental/ecological costs they are in reality an expensive option.
Changing to alternative methods can be time consuming and a certain amount of training in insect identification is necessary to overcome this hurdle. Other benefits such as greater awareness of what is happening in the agroecosystem will come from this in addition to economic and environmental gains. So long as growers and advisors are supported by trained entomologists and researchers this barrier can be easily overcome.
Advisors are often inexperienced in IPM strategies, an issue which is easily addressed through education and extension through this and parallel IPM initiatives.
There may be an initial increase in levels of damage during the transition phase while populations of beneficial recover following a past history of broad spectrum insecticide use. The time it takes for beneficial populations to resurge will depend on past and surrounding pesticide usage as well as other environmental variables such as landscape vegetation patterns and climate.
Further more detailed information on Integrated Pest Management is available from a number of agencies and institutions (see links section).