The spotted lanternfly, Lycorma delicatula, has emerged as a significant invasive pest in North America. This planthopper, recognizable by its distinctive wing patterns, poses a considerable threat to agriculture and forestry.
Where They Come From
The spotted lanternfly is indigenous to Asia, including China, India, and Vietnam. In China, it primarily feeds on the tree of heaven, Ailanthus altissima. Its native habitat often features temperate to subtropical climates, providing suitable conditions for its life cycle. Within these native environments, natural predators, parasites, and pathogens help regulate its populations.
These natural controls, such as parasitic wasps that target its eggs and nymphs, keep its numbers in check. Fungi and other insectivorous creatures also contribute to maintaining a natural balance. The presence of these biological agents helps to prevent unchecked population growth, which contrasts sharply with its behavior in introduced regions. This ecological balance is a key factor in understanding its invasive success elsewhere.
Their Unintentional Trip
The spotted lanternfly was accidentally introduced to the United States through international trade. The most accepted theory suggests that egg masses, which are camouflaged and resemble patches of mud, arrived on imported goods. These goods likely included stone, freight materials, or other products shipped from its native range in Asia. The durable nature of the egg masses allows them to survive long journeys across oceans.
The first confirmed detection of the spotted lanternfly in the United States occurred in Berks County, Pennsylvania, in September 2014. This initial introduction was entirely unintentional, a byproduct of global commerce. The insects likely hatched from these egg masses after arriving, beginning a new population in an unfamiliar environment.
How They Took Hold
Once established in Pennsylvania, the spotted lanternfly rapidly expanded its range due to several contributing factors. A primary mechanism for its spread is human-assisted dispersal, or “hitchhiking,” facilitated by its habit of laying egg masses on almost any flat surface. These surfaces include vehicles, shipping containers, outdoor furniture, and even railway cars, allowing the insects to travel considerable distances unknowingly. Adult lanternflies can also fly short distances and cling to vehicles, further aiding their movement.
The absence of natural predators and parasites in its new environment has allowed the spotted lanternfly populations to grow unchecked. Unlike in Asia, where various organisms prey on or parasitize the lanternfly, these biological controls are largely missing in North America. This ecological void removes a significant barrier to population expansion. The insect also exhibits a high reproductive rate, with each female capable of laying multiple egg masses, each containing dozens of eggs.
Furthermore, the spotted lanternfly’s broad host range contributes to its ability to thrive in diverse landscapes. While it prefers the tree of heaven, it can feed on over 70 different plant species, including economically important crops like grapes, hops, and fruit trees, as well as various hardwoods. This combination of factors enabled the rapid establishment and proliferation of the spotted lanternfly beyond its initial introduction site.