Publisher Summary This chapter discusses Colorado potato beetle or Leptinotarsa decemlineata (Coleoptera: Chrysomelidae), which is the most devastating, defoliating insect pest of potato (Solanum tuberosum ). The potato beetle is important because of the damage it causes to potato and some related crops, as well as its extraordinary ability to evolve resistance to insecticides used in its control. The host range of the Colorado potato beetle is largely restricted to plants in the genus Solanum. The Colorado potato beetle is primarily a pest of potatoes but may also damage tomato (Solanum esculentum) and eggplant (S. melongena ). In potato, yield reductions are related to both the amount of defoliation and the stage of plant growth during which it occurs. Yield reductions in tomato and eggplant result from feeding injury to the fruits as well as from defoliation. A series of insecticides was used in previous studies to control the beetle but they developed resistance to each of them. This stimulated a burst of research activity, which resulted in development of more holistic pest management approaches but none of them succeeded. Over time, it is likely that these concerns will diminish and transgenic potatoes will become an important tool for managing Colorado potato beetle.