Landscape considerations in pest management: Case study of the Arizona cotton IPM system

Integrated pest management (IPM) for cotton in Arizona has been under continual evolution for many decades. For over 30 years its foundation has rested on the careful integration of avoidance tactics, thresholds, sampling, and the use of selective insecticides and technologies to foster conservation biological control along with a crucial community-based approach to enable broad-scale education of and adoption by cotton growers and their consultants. The success of this strategy and its evolution involves both implicit and explicit consideration of the landscape context because all the key insect pests of this system are mobile, and several are highly polyphagous. Most tactics such as sampling, thresholds, effective insecticide use, conservation biological control, and crop management are practiced on individual farms. But because many growers use these tactics, they have profound regional impact on pest and natural enemy populations. Cotton growers explicitly engage in cooperative practices such as pest eradication, insecticide resistance management, and crop placement that contribute further to sustainable IPM on a landscape scale. Many of these gains were enabled through the development of new "hard" technologies such as Bt cotton and selective insecticides. However, the Arizona cotton IPM system's success is rooted in the research, development, and deployment of the requisite set of "soft" technologies or use instructions needed to collectively implement individual practices and harness the power of landscape-level cooperative management. The overall result has been a savings of over US$600 million in control costs and yield loss savings for growers since 1996, along with an associated 85-90% reduction in insecticide use, and an increasing focus on natural control elements as the engine driving further innovations. Here we discuss the development, implementation, and evolution of the cotton IPM program for Arizona, with emphasis on the critical importance of a landscape perspective for its current and future success.