Spotted Lanternfly
First found in Pennsylvania in 2014, the spotted lanternfly has become a notorious pest in the Northeast and is steadily moving west. This visually striking planthopper, native to China, is a major threat to agriculture. It feeds on the sap of over 70
plant species, with a strong preference for grapevines, apple orchards, and hardwood trees. As it feeds, it excretes a sugary substance called honeydew, which promotes the growth of sooty mold that can damage or kill plants underneath. Its rapid spread has been aided by its life cycle; the insect lays mud-like egg masses on almost any flat surface, including cars and shipping materials, allowing it to hitchhike across state lines with ease. States from Virginia to Indiana have reported infestations, and its continued expansion threatens billions of dollars in agricultural revenue.
Asian Longhorned Tick
Native to East Asia, the Asian longhorned tick was first detected in New Jersey in 2017 and has since spread to numerous states, primarily in the eastern U.S. Unlike most tick species, a single female can reproduce without a mate, allowing one tick to create a new population. This ability contributes to its rapid expansion. While they are not yet known to have transmitted diseases to humans in the U.S., they are a significant threat to livestock. Heavy infestations can cause stress, reduced growth, and even death in cattle and sheep. In its native range, the tick transmits several pathogens, including one that causes severe fever with thrombocytopenia syndrome, a potentially fatal hemorrhagic fever in humans. Scientists are closely monitoring its spread into new regions like the Midwest.
Red Imported Fire Ant
A familiar and painful pest in the South, the red imported fire ant continues its relentless march into new territories. Accidentally introduced into Alabama around 1940, it now infests more than a dozen states from Florida to California and is pushing northward. These aggressive ants are known for their painful, swarming stings that can cause severe allergic reactions. They build large, unsightly mounds in lawns, parks, and agricultural fields, disrupting outdoor activities and damaging equipment. Climate models suggest their potential habitat could continue to expand into parts of Virginia, Maryland, and even into western states like Oregon and Nevada, especially in irrigated areas. Their spread is often aided by the transport of nursery stock and soil from infested regions.
Zebra and Quagga Mussels
These tiny, sharp-shelled mollusks have been wreaking havoc on American waterways since they arrived from Eastern Europe in the 1980s, likely in the ballast water of ships. First established in the Great Lakes, they have since spread through the Mississippi River basin and into hundreds of inland lakes and rivers across the country, reaching as far as Texas and California. Zebra and quagga mussels are filter feeders that strip plankton from the water, which devastates the food web for native fish and birds. They form dense, crust-like colonies on any hard surface, clogging the water intake pipes of power plants and city water supplies, costing industries millions of dollars annually for removal. Their westward spread continues, primarily by hitching rides on uncleaned recreational boats.
Emerald Ash Borer
Since its detection near Detroit, Michigan, in 2002, this metallic green beetle from Asia has become one of the most destructive forest pests in North American history. The beetle's larvae tunnel under the bark of ash trees, cutting off the flow of water and nutrients and killing the tree within a few years. The emerald ash borer has killed hundreds of millions of ash trees across more than 35 states and is continuing to spread, with new infestations appearing in western states. The primary driver of its long-distance spread is the movement of infested firewood, logs, and nursery trees. The loss of ash trees has profound ecological consequences and has cost municipalities and homeowners billions in removal and treatment costs.
