The Scale of IPM Systems

Most IPM programs focus on single fields because of local variability in physical, crop, and pest conditions. Some pests, however, are highly mobile and require a regional approach for their control. Furthermore, certain control tactics are effective only if deployed over large areas. Mating disruption for control of the codling moth in apple and pear orchards in the western United States used an area-wide approach that required a minimum operational unit of about 160 hectares. Advancement of IPM to higher levels of integration will require planning and implementation at the landscape or even ecore- gional levels. Advanced technologies of geographic information systems (GISs) and remote sensing are essential for the development of such programs. Such planning is still at its infancy in IPM.

Decision Support Systems for IPM Implementation

IPM uses objective criteria for making decisions about the need for a control action and selection of the most appropriate tactics. In arthropod pest control, the criteria are based on assessments of the extant pest population in the field, its damage potential (if not controlled), and the relative costs of treatment and crop value. The main parameters are the EIL and economic threshold (ET). ET is the population level that will trigger a control action. Figure 21.1 describes these parameters. To use ETs, it is necessary to monitor pest populations in the field using well-defined sampling methods, which vary with the pest species. Although useful, the concept of EIL is less effective as a decision-making support tool for weed management and is partially applicable to microbial disease management.1201

IPM Education and Extension

Since the establishment of the Land Grant Universities (1890), teaching of entomology and plant pathology was gradually introduced in the curricula. Courses on insect science that included the control of agricultural pests were variously designated as applied, economic, or agricultural entomology. As faculties expanded in plant protection departments, specialized courses were introduced in chemical pesticides, biological control, host plant resistance, and others. With the introduction of IPM in the late 1960s, most entomology departments started offering basic IPM courses at the undergraduate level and advanced IPM for graduate students. One of the first entomology textbooks aimed at teaching IPM was by Metcalf and Luckmann.12'! Other texts followed. Pedigo’sl221 Entomology and Pest Management, first published in 1989, became the standard for introductory courses in insect IPM in the United States, and Dent’sl231 Integrated Pest Management probably had the same role in the United Kingdom. Although IPM continues to be taught mostly along disciplinary boundaries, a few universities offer multidisciplinary courses combining entomology, plant pathology, and weed science within integrated curricula. The book by Norris, Casweil-Chan, and Kogan121 was the first to offer an interdisciplinary text for IPM teaching.

Fundamental decision-making concepts for insect pest management

FIGURE 21.1 Fundamental decision-making concepts for insect pest management: ET and EIL. Illustrated is an insect pest population with two peaks in lyear. The first peak remains below ET, and no treatment is needed; the second peak exceeds ET. If a treatment is applied, the population crashes (curve A); if a treatment is not applied, the population exceeds EIL and an economic crop loss occurs (curve B).

It is the role of agricultural extension specialists to bring to growers the most up-to-date information on IPM technological advances and promote adoption of effective IPM systems. Extension specialists use demonstration plots, field days, intensive short courses, special publications, and increasingly, the power of the Internet, to expose growers to the latest in IPM. Formerly printed IPM information is now available online, which allows for more timely updates and ease of access to the information. An example is the Pacific Northwest IPM Handbooks that had been traditionally issued once a year in three volumes for insect pests, plant diseases, and weeds. These are now entirely published online.1241 One critical area for IPM implementation involves decision support systems. Online degree day-driven pest development models are available to help growers in the optimization of sampling and timing of control actions.1251 In developing regions of the world where computers are still rare in rural areas, extension has been highly effective with a model developed by specialists of the Food and Agriculture Organization (FAO) in collaboration with international research centers. The model known as farmer field schools is a participatory approach in which extension specialists and farmers meet in the field to identify pest problems and discuss possible solutions. First tested in Southeast Asia,1261 the approach has been successful in Africa also.1271 Maintaining the flow of information from research laboratories and experimental fields into the classroom and the farm is essential to expand IPM adoption.

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