The goal of Integrated Pest Management (IPM) is to rationalize or reduce pesticide use. IPM differs from approaches used in organic farming in that it involves the use of synthetic chemicals where necessary. It is based on the premise that no single pest management tool is ever likely to be completely successful. It is flexible enough to incorporate some of the new crop protection approaches available through genetic engineering.
In practical terms IPM strategies rely on some combination of: (1) monitoring of pest population levels; (2) biological control using predatory or parasitic insects; (3) cultural/physical controls, such as pruning, water management and sanitation; (4) host plant resistance; and (5) chemical control, through the judicious application of pesticides.
Birds, insects, rodents and other organisms can consume and destroy significant proportions of annual agricultural production. Numerous methods to control pests have been used including pheromones, biological controls such as natural predators, chemicals such as pesticides, herbicides and fungicides, and breeding disease-resistant plants. These methods can lead to successful pest control, but also to negative environmental impacts from their mismanagement and over-application. Pest control programmes may not eradicate all pests because of programme specificity and increased pest resistance. Successful and more environmentally friendly pest control may be achieved by combining pest control methods in an integrated pest management approach.
Pest management options that fit into the approach of Integrated Pest Management (IPM) include biological, mechanical and chemical crop protection measures as well as biotechnology. Modern pest management is based on prevention, careful monitoring of crop health (pressure from disease, weed and pest populations) and expedient interventions. Natural control processes - through techniques such as crop rotation and encouraging beneficial pest predators - also help to avoid outbreaks.
This strategy features in the framework of Agenda 21 as formulated at UNCED (Rio de Janeiro, 1992), now coordinated by the United Nations Commission on Sustainable Development and implemented through national and local authorities.
Pest management practices include: manipulation of crop rotations, to minimize survival of crop-specific pests (in the form of, i.e., insect eggs, fungi) which can infest the next crop; strip cropping, to moderate spreading of pests over large areas; manipulation of pH-level or moisture level of the soil (in irrigated areas); manipulation of planting dates, to plant at a time most optimal for the crop, or least beneficial for the pest; adjustment of seeding rates, to achieve an optimal rate given the need to crowd out weeds or avoid insects; use of appropriate plant varieties and livestock breeds for local conditions; implementation of stock culling programmes, which emphasize genetic resistance against certain diseases; use of stock buying programmes, which minimize the import of diseases onto the farm; limiting field size, which aids in weed management by livestock; biological control methods, to encourage natural enemies of pests by providing habitat (i.e. hedges) or by breeding and releasing them in areas where they are required; trapping insects, possibly with the use of lures such as pheromones; biological pesticides (i.e., derris dust, pyrethrum, rotenone) of which the active ingredient is short-lasting, and which may be produced locally.
The UN Food and Agriculture Organization (FAO) and the United Nations Environment Programme (UNEP) have assisted developing countries in the implementation of integrated pest management and also jointly co-sponsor the Panel of Experts on Integrated Pest Control in Agriculture.
In the mid-1980s, Indonesia initiated the biggest IPM programme ever attempted in order to combat the massive outbreaks of the rice-destroying insect, brown plant hopper. Three legislative strategies were employed: (1) 57 chemicals deemed responsible for the pest outbreak were banned for use in rice; (2) government subsidies on many other chemicals were cut from 85% and gradually reduced to zero over a three year period; (3) IPM became national policy. There was also a massive programme of farmer participation and training. Training was interactive and non-directive, centering on word-of-mouth information.
Consumer demand has been the most important influence on the penetration of integrated pest management in westernized country with completely market-oriented systems. Consumer-driven introduction of IPM is proceeding rapidly in north-western Europe. The second source, government-driven IPM, goes very slowly. Farmers have a long standing tradition of mistrusting the messages of governments. Sweden, the Netherlands and Denmark have taken policy decisions of pesticide reduction without mentioning IPM explicitly. Here the combination of heightened public concern over pollution by pesticides and emphasis on agricultural competitiveness have combined to steel government action.
One difficulty associated with integrated pest management is the cost of providing a continuous diet for the predators when supplies of pests fall. In California at the Department of Agriculture, work is underway to develop artificial diets for the beneficial insects, thus far with limited success.