Potato, Solanum tuberosum, is a native of South America. Potatoes were cultivated and bred by Mayans and improved varieties were an important component of South American crop production when Europeans first visited in the 1500s. Potatoes generate one of the highest calories per acre value of any food crop. The potatoes grown by the Mayans had some pests, but not the Colorado Potato Beetle. In the 1500s, the Colorado Potato Beetle was present in what is now Northern Mexico and the Western United States where it fed on plants in the potato family. It was not called the Potato Beetle and it did not feed on potatoes because potatoes were not grown in that area until the mid 1800s.
Potatoes have been transported around the globe and have established as an important food crop in many areas. Colorado Potato Beetle was not yet a pest and not present in any of these new areas for growing potato. Early European colonists in North America had no problems with Colorado Beetle over several centuries of potato production. The Beetle was trapped in an isolated region of North America. Outside its natural range, there were no suitable hosts. Its range was limited.
The trouble started in the 1850s. Potato production continually moved west along with European settlers, eventually reaching western Nebraska. Infestations of Colorado Potato Beetle were first reported in 1859 Nebraska. Settlers had moved the potato into the native range of the Colorado Potato Beetle. The sudden appearance of a new suitable plant led to a shift in host plant. The beetle found potatoes to be suitable and adopted potatoes as a host. By 1859, potatoes were grown in farm patches from the East Coast of the United States to Nebraska and Colorado. The Beetle was presented with a “Highway of Potatoes” stretching from Nebraska to the Sea. The beetle began a steady march across the continent that brought them to the Atlantic Ocean in 20 years. At that time the expansion slowed. However, less than half a century later, a new opportunity for expansion arose.
In 1921, Colorado Potato Beetle was found in Europe where it resisted measures for eradication or control. The Beetle began a new march across a new continent. Fifty years after it was introduced to Europe, the Colorado Potato Beetle reached Central Asia in the 1970s. Potato Beetle was first documented in China in the 1993, after crossing the border from neighboring Kazakhstan. Liu and colleagues review the invasion of the Colorado Potato Beetle in China in an Entomologia paper.* The Beetle is slowly expanding its range in Eastern China and continues to move East. It might be possible to slow the spread of this pest but that would be a monumental task. Most likely the Colorado Potato Beetle will soon enter the major potato producing region of China and keep marching East until it reaches the Pacific Ocean.
*Entomologia Experimentalis et Applicata. Volume 143, Issue 3, pages 207–217, June 2012