Michigan Field Crop Pest Ecology and Management (E2704)
October 27, 2015 - Author: Dale R. Mutch
Liberty Hyde Bailey's perspective is at the heart of this publication. Its predecessor, Michigan Field Crop Ecology (MSU Extension Bulletin E- 2646) introduced producers and educators to the idea of looking at farms as ecosystems, and recognizing that farms are habitats for many organisms other than crops, livestock and pests. These organisms form an integrated web that allows farms to function. That publication's major theme focused on understanding how management practices affect those organisms' food sources and habitats. Producing economically viable crops while preserving and enhancing both the farm fields and the surrounding ecosystems requires understanding a farm's ecology. That bulletin also emphasized that because of the great variability in soils, microclimates and other factors, farmer participation is crucial for developing more sustainable agricultural systems.
Michigan Field Crop Ecology readers have requested more pest management information for field crop ecosystems.
This volume comes in response to that demand. Some insects, disease-causing organisms (pathogens), nematodes and weeds compete with humans for field crop resources. Left unmanaged, these pests reduce crop yield and quality.
In the past 50 years, pesticide use has become the dominant pest management strategy. There is a growing consensus, however, that relying on chemically based pest management systems is neither desirable nor sustainable. Pesticides may threaten human and environmental health, pests are becoming more resistant to pesticides and legislative action is reducing pesticide options. Alternative pest management strategies are needed. This bulletin will help readers understand the ecological principles that can be used to manage field crop pests in new and more effective ways.
What are field crop pests?
Pests are organisms that cause economic damage to crops. In this bulletin we will look at weed, insect, plant pathogen and nematode pests. Pests exist in both managed and natural ecosystems. Their impacts are often more severe in agricultural systems because humans often create conditions in agricultural systems that favor crop pests but not their natural enemies.
What is pest ecology?
Pest ecology is the study of the interactions between pests, their environment and other organ isms. All organisms are regulated by both abiotic (non-living) and biotic conditions and other organ isms. Abiotic factors that can limit pests include temperature extremes, light and water. Biotic factors controlling pest populations include a pest's natural enemies (predators, pathogens and parasites) and competitors.
In unmanaged or natural ecosystems there is usually balance among organisms. As the population size of a pest organism increases, it becomes an abundant resource for its natural enemies, which then increase in number and drive the pest population size down. As its food becomes scarce, the natural enemy population size also declines, producing an ongoing cycle that results in population regulation. Since organisms in unmanaged or natural ecosystems are often controlled by more than one natural enemy or competitor, the population size of any one species rarely reaches epidemic outbreak proportions.
What is field crop pest ecology and management?
Ecologically based pest management makes full use of understanding pest ecology, including farm conditions that the farmer knows best. In field crop ecosystems, we often create situations where pests have excess resources but few, if any, limiting factors. By understanding how pests take advantage of field crop situations, we can work to limit their success. For example, common ragweed is frequently found in wheat stubble where there is plenty of light and moisture and little competition. Frost seeding a legume into wheat increases competition for light and moisture, reducing ragweed population density.
A legume cover crop also provides nitrogen to the succeeding crop, helps prevent soil erosion, increases soil organic matter levels and may help control insect and nematode pests by providing a favorable environment for their natural enemies. Management strategies that provide multiple benefits are a key component of ecologically based pest management.
By explaining ecological interactions among field crop pests, abiotic factors, natural enemies, competitors and crops, we hope this volume will spur readers' interest and ideas for ecologically based pest management strategies.
For further reading
National Research Council. 1996. Ecologically Based Pest Management: New Solutions for a New Century. A report of the Committee on Pest and Pathogen Control through Management of Biological Control Agents and Enhanced Cycles and Natural Processes, Board on Agriculture. National Academy Press. Washington, D.C. 146 pp.
U.S. Congress, Office of Technology Assessment. 1995. Biologically Based Technologies for Pest Control. OTA-ENV-636, U.S. Government Printing Office. Washington D.C. 204 pp.