Integrated Pest Management of Insects, Plant Pathogens, and Weeds in Dryland Cropping Systems of the Great Plains

In this article, we trace the development of the concepts and practices of Integrated Pest Management (IPM). Tactics used in IPM of insect pests, plant pathogens, and weeds are discussed, with particular emphasis on application to dryland cropping systems of the Great Plains. Recommendations are made for guiding the development of IPM in such systems. IntroductionInsect pests, plant pathogens, and weeds pose a considerable threat to the dryland cropping systems of the Great Plains. The concepts and practices of Integrated Pest Management (IPM) provide an approach to managing these pests. The objectives of this paper are to review and synthesize existing information about IPM and to discuss the application of IPM specifically in the dryland cropping systems of the Great Plains. Literature SummaryMany descriptions of IPM have been provided in the literature. The description used here is: “IPM is the judicious use and integration of various pest control tactics, in the context of the associated environment of the pests, in ways that complement and facilitate biological control and other ecological processes that reduce pest impact, to meet economic and environmental goals. IPM addresses the basic causes of pest problems in a holistic manner.” Table 1 lists categories and sub-categories of IPM tactics. Decisions regarding what tactics to use and when and how to use them are a critical aspect of IPM, The concept of the economic injury level (EIL) was developed as a decision tool for managing insect pests in the 1950s and has become a major component of IPM. There are, however, limits to its usefulness, particularly in dryland cropping systems. Study DescriptionPublished IPM practices specific to the dryland cropping systems of the Great Plains were reviewed and discussed, with particular emphasis on the use of the EIL and the tactics of pest resistant cultivars, crop rotations, and planting date. In addition, management systems were reviewed for wheat streak mosaic virus, wheat stem sawfly, and Russian wheat aphid. Applied QuestionsWhat are the IPM tactics that are most appropriate for IPM in dryland cropping systems of the great plains? The tactics to be emphasized in dryland systems are those that can be designed into the cropping system to reduce the likelihood of pest problems developing. Examples are: cultivars resistant to the pest, crop rotations, certain types of biological control, and planting date adjustment. Tactics such as pesticides, that are applied once a pest problem is active, have limited usefulness because of the expense of gathering information about the current status of pests and the cost of applying the tactic. In low value, dryland cropping systems, the potential increase in economic return from the use of these tactics typically does not justify the cost. Is the EIL concept useful in IPM in the dryland cropping systems of the great plains? Yes. However, its usefulness is limited by the relatively low value of the crops grown in dryland systems and the expense associated with acquiring and interpreting the information required for use of the EIL in IPM decisions. Another important limitation to the usefulness of the EIL is the expense of applying the tactics (mostly pesticides) that are available for use against an active pest problem. RecommendationsTo best meet the needs for IPM in the dryland cropping systems of the Great Plains, management tactics must be built into cropping systems design. This will require a systems approach with teams of individuals from many disciplines working together. Adoption of such systems will be enhanced if the teams include expertise in research and extension and if producers are closely involved from the earliest stages. Table 1IPM tactics. PesticidesHost plant resistanceBiological control Importation and release Conservation AugmentationCultural practices Rotations lnterplantings Cover cmps Planting density Pest-k planting materials Planting date Harvesting date Tillage Sanitation Field size Adjacent land uses Soil fertility management lmgation management