ABSTRACT
The ecosystem consists of the pest population and the surrounding interactive biotic and physical environment. The interactions between a single pest species and its environment are enormously complex, and all too frequently we are also faced with the necessity to manage a number of pests forming a “pest complex” associated with a single plant species. In an agricultural landscape there are usually several crops grown simultaneously, such as corn, soybeans, alfalfa, and wheat on farms in the midwestern U.S., or beans, squash, tomatoes, peppers, lettuce, and radishes in my own backyard garden. These plants coexist within a matrix of surrounding ecosystems each with its typical flora and fauna: abandoned weedy fields, hedgerows, forests, and so forth. Ecological processes within these surrounding habitats influence events within adjacent agricultural or landscaped ecosystems. In agricultural production we may cast aside the complexity and unpredictability of these ecological processes, and we may oversimplify, ignore, or override these ecological processes as best we can, with the appropriate goal of maintaining or increasing yields with minimal (financial) input in order to make a profit. However, our efforts to manage pests often disrupt whatever naturally occurring pest population regulation or “equilibrium” there may be, and we may be forced to commit additional environmental disruption to achieve economic goals. Even very successful integrated pest management (IPM) programs often display little attention to or appreciation of ecosystem functions (Kogan, 1986, 1995).
