In late 2014, a group of spotted lanternflies, an insect native to China, were inadvertently imported to the United States. They were first discovered near Reading, Pennsylvania, in September of that year. In the decade since, this invasive species, abbreviated SLF, has colonized Pennsylvania and the New York metropolitan area, and is gaining a foothold in the DMV, with further expansions into the Midwest, New England, and the Upper South likely. Unlike true flies, spotted lanternflies travel primarily by hitchhiking rather than flying, and have unique reproductive patterns. The SLF’s rapid expansion in the northeastern United States has been aided by their propensity to lay eggs on vehicles and even clothing, which can introduce the insect to different counties or states. Spotted lanternflies are considered destructive pests, and unlike common invasive insects such as the emerald ash borer, feed on a broad range of crops and trees by perforating bark and phloem and extracting sap. The tree-of-heaven, another invasive species originating in China, is their natural preferred host, and can be found in similar abundance across the United States, especially on the West Coast, which is at risk of becoming a second stronghold of SLF infestation if they are introduced to that area.

A number of state governments, including Virginia, have put infested counties under quarantine, granting the state the authority to regulate any activity, such as agriculture, landscaping, or camping, that might increase the spread of lanternflies. People traveling from areas under SLF quarantine must inspect their vehicles, clothing, and personal items for all life stages. Egg clutches are small, flat, white-to-light-brown patches that resemble mold or cracked mud, while nymphs are black with white spots, progressing to red and black with white spots in later stages. Adults are an inch long and have two pairs of wings: a brown outer set with black spots, and a red inner set with black spots and brown tips. Those who encounter any stage of SLF are advised to destroy it immediately, and if found in a location not currently under quarantine, should inform their state’s Department of Agriculture.

Efforts to reduce lanternfly populations by sterilizing and releasing groups of male SLFs, who then sire clutches of eggs that do not hatch (as has been done with certain breeds of mosquito), are unlikely to prove successful due to females’ propensity to mate with different partners and lay eggs multiple times over their one-year life cycle. One method of reducing SLF populations that has been successful involves wrapping sticky tape around tree trunks, which traps the lanternflies as they climb (SLFs can fly, but, like bees, they generally prefer to crawl). However, this method can cause collateral damage to benign or helpful species, including pollinators. Other popular methods to reduce harm to other species include installing mesh wiring around the sticky tape, which prevents birds from trapping themselves as they attempt to eat lanternflies, and more expensively, using a variant of the “circle trap”, which has been successfully deployed against other pests.

Given the failure of existing quarantines to substantially halt the expansion of SLF infestations, it is likely that lanternflies will continue their conquest of the United States, at least until they reach the High Plains, which are inhospitable to the tree-of-heaven, and where other hosts are not commonly grown. With the lanternfly’s high mobility and rapid reproductive cycle, individual states are unable to extirpate their SLF populations without a comprehensive federal strategy. For its part, the USDA released a five-year plan last year which centers on preventing new infestations, but lacks a blueprint for reclaiming already-infested regions.