Insect Pests That Crossed Borders and Outran Their Controls

Native to Mexico or Central America, the boll weevil reached United States cotton in the late nineteenth century. Its spread through the American South in the early twentieth century devastated the regional cotton economy, and the long federal eradication program that followed is a landmark case in area wide pest management.

Native to the Rocky Mountain region of North America, this striped beetle spread across the United States and into Europe and Asia over the twentieth century. Its larvae and adults defoliate potato, tomato and eggplant, and it is notorious for evolving resistance to nearly every class of insecticide used against it.

Native to Central America, this beetle moved through the United States Corn Belt over the twentieth century and reached Europe in the 1990s. Its larvae feed on maize roots, and it has repeatedly evolved resistance to crop rotation, insecticides and Bt maize traits.

Native to sub-Saharan Africa, the medfly has larvae that develop inside more than 300 kinds of fruit and vegetables, causing internal rot that makes produce unsellable. It is now established around the Mediterranean, in parts of the Americas and in Australia, and the threat to fruit exports has driven some of the largest sterile insect technique eradication programs ever run.

Native to East Asia, this shield-shaped bug was accidentally introduced to the United States in the 1990s and has since spread across much of North America and into Europe. It feeds on a very broad range of fruit, vegetable and row crops, and severe outbreaks have cost orchard growers tens of millions of dollars in single seasons.

Native to South and Southeast Asia, this large beetle has spread through the Middle East, the Mediterranean and parts of the Caribbean. Its larvae bore through palm trunks, often killing the tree before the infestation is detected, which threatens commercial date production and ornamental palms alike.

Native to the Americas, the fall armyworm spread to sub-Saharan Africa in 2016 and then across Asia and Australia within a few years. Its caterpillars feed on more than 80 plant species, with maize, sorghum and rice the most damaged, and African maize losses alone are estimated in the billions of dollars each year.

Native to South Asia, the khapra beetle infests stored grain, seeds and dried food, and tolerates extreme heat, cold and starvation better than most stored product pests. Because established infestations are extremely difficult to eradicate, many countries apply strict quarantine controls to it.

The caterpillars of this moth bore into the fruiting bodies of cotton, maize, sorghum, chickpea and tomato across Africa, Asia, Europe and Oceania. It is considered one of the most economically damaging insect pests in the world and has developed resistance to numerous insecticides and to some genetically modified insect resistant cotton varieties.

Found on every continent except Antarctica, this small moth feeds only on cruciferous plants such as cabbage, broccoli, canola and mustard. It was the first insect documented to develop resistance to DDT and has since evolved resistance to nearly every insecticide class used against it, with management costs estimated at billions of dollars a year.