Biological control agents often have a close relationship with the host plant. For example, predatory mites use chemical messengers produced by the plant in response to spider mite feeding to locate their prey. Predators and parasites may require nectar, pollen, or other plant products for alternate food. Morphological characteristics of plants such as leaf or stem hairs may affect searching ability of natural enemies. Therefore, changing to cultivars with different susceptibility to pests can also affect biological control agents, which in turn affect pest population. Scientists call these tritrophic interactions.
Integrated Pest Management (IPM) was developed to reduce the use and impact of pesticides in energy intensive agriculture. Use of IPM has and continues to do this in many agricultural systems, but in most systems, use of pesticides remains the predominant tactic. However, is high input agriculture sustainable or even desirable? Plants are the focus of most agricultural crop systems, not the plant's pests. Pests, in reality, are often symptoms of the limitations of current culture and management practices, or aggravated by them. The goal of producers is not to raise pests. In fact most agricultural organisms are not pests. Ideally, we should minimize inputs by using the natural components of the ecosystem for suppressing pests beginning with host plant resistance, biological control and cultural and management practices. We then rely on chemicals as a last resort. This is what IPM professes to do.
Focusing on Integrated Pest Management as opposed to crop management or some other term for the entire system puts misplaced emphasis on pests. Self-interested scientists in pest control disciplines may think this way, growers do not. Moreover, pest management takes on a life of its own over and above the management of the crop (product) that often excludes the impact and contributions from other plant science disciplines such as agronomy, plant breeding and horticulture. What results is single disciplinary, reductionist science. While IPM is rooted in applied ecology, the holistic system with all its components may influence pest abundance. Every component of the system from soil to sunlight may be adjusted or manipulated to suppress pests. Most growers view their operations as a system with multi-components, so should research and extension scientists. To optimize use of the functional components of the agroecosystem to suppress pests and become sustainable will require a concerted effort by all disciplines that reconciles philosophy, theory and practice for all agricultural disciplines. This implies a dramatically different approach to research and extension than is the norm at most land grant universities today. We advocate the evolution of the IPM concept into a whole systems crop management approach.
"IPM stresses holism, utilizing agroecological principles but translating them into a socio-economic framework which stresses human resources development". Teng & Savary. 1992. Agric. Syst. 40:237-64.
For additional information visit the Florida IPM and Biocontrol Web site at http://biocontrol.ifas.ufl.edu/.