The spotted lanternfly (Lycorma delicatula) is an invasive planthopper that was first detected in Pennsylvania in 2014. Native to parts of Asia, this insect possesses a high reproductive rate, with females laying egg masses containing 30 to 50 eggs each on nearly any hard surface. The rapid spread of this pest poses a serious threat to agricultural and timber industries, prompting large-scale efforts from government agencies and the public to contain its movement and manage established populations.
Current Geographic Spread
The spotted lanternfly has spread from its initial outbreak zone in eastern Pennsylvania to establish populations in at least 19 states plus the District of Columbia. States along the Mid-Atlantic host the most established populations, but new detections have occurred as far west as Illinois and as far south as Georgia and South Carolina. This expansion is primarily driven by human activity, as the insect is an adept hitchhiker that lays egg masses on vehicles, pallets, outdoor furniture, and firewood.
To slow this movement, state and federal authorities have implemented quarantine zones where the movement of “regulated articles” is restricted. The quarantine requires businesses and residents to inspect and clean items before transporting them out of an infested area. Warmer temperatures in urban areas may also be facilitating the insect’s ability to spread farther north.
Economic and Environmental Impact
The primary agricultural concern is the damage the spotted lanternfly inflicts upon vineyards, fruit trees, and hops. In vineyards, high populations feed directly on the sap, weakening the vines, leading to reduced yields and vine death. The impact on industries like grapes, tree fruit, and ornamentals is valued in the billions, with statewide economic losses projected to reach hundreds of millions of dollars annually.
Beyond agriculture, the insect creates a nuisance through its feeding habits on over 70 different plant species. As the lanternflies consume plant sap, they excrete excess sugary fluid known as honeydew. This sticky substance coats plants and surfaces, providing a medium for the growth of black sooty mold. The mold weakens plants by blocking photosynthesis and reduces the aesthetic quality of ornamental trees and outdoor equipment.
Strategies for Population Control
Regulatory Control
Human efforts to manage the spotted lanternfly population employ a multi-pronged approach combining regulatory, mechanical, and chemical strategies. Regulatory control involves the establishment of quarantine zones and the mandatory permitting process for businesses that move goods and materials. This is designed to minimize human-assisted spread and is supported by public outreach campaigns urging residents to inspect their vehicles and outdoor items before traveling.
Mechanical Control
Mechanical control methods focus on physically eliminating the insects and their eggs. These actions include scraping egg masses off hard surfaces during the late fall and winter months. Another common method involves wrapping tree trunks with adhesive bands or specialized circle traps to capture the flightless nymphs as they crawl up host trees.
Chemical Control
Chemical control is deployed in high-infestation areas, particularly those with valuable agricultural crops or ornamental landscapes. Systemic insecticides are applied as soil drenches, bark sprays, or injections, allowing the chemical to move throughout the plant tissue to kill the feeding insects. Contact insecticides are also used for immediate, localized treatment of nymphs and adults. Furthermore, efforts are made to remove the spotted lanternfly’s preferred host, the invasive Tree-of-Heaven (Ailanthus altissima), which can harbor large populations of the pest.
Natural Enemies and Population Dynamics
Ecological factors are beginning to influence the spotted lanternfly population, separate from human intervention. Generalist native predators, including praying mantises, spiders, and the spined soldier bug, have been observed feeding on the lanternflies in North America. These predators consume the insects even if they have fed on the Tree-of-Heaven, suggesting the pest’s chemical defenses may not deter all native species.
Scientists are also investigating specialized natural enemies from the insect’s native range in Asia for potential controlled release programs. This includes the egg parasitoid wasp, Anastatus orientalis, and the nymphal parasitoid, Dryinus sinicus. The introduction of A. orientalis is complex due to the risk of it parasitizing the eggs of native North American insects.
In older, more established areas like the outbreak zones in Pennsylvania and New Jersey, observations suggest that the spotted lanternfly population has begun to peak and subsequently decline after four to five years. This pattern is often seen as invasive species establish new ecological pressures in an environment.