This chapter will review current insect pest monitoring systems for native and invasive pest species of corn, soybean, and cotton in the U.S. We present case studies of European corn borer, corn earworm, western bean cutworm, and corn rootworm as pests of corn; soybean aphid, stink bugs, and Japanese beetle as pests of soybean; and tobacco thrips, plant bugs, and bollworm as pests of cotton. We discuss how new technology has driven recent improvements in monitoring of these pests from the lab, field, and areawide levels. Although the primary emphasis will be the value of pest monitoring to support improved decision-making for IPM programs, we also discuss recent trends and tools for insect resistance management (IRM), since the importance of some field crop pests has increased as resistance continues to evolve.