The spotted lanternfly, Lycorma delicatula, is an invasive planthopper first detected in North America in Pennsylvania in 2014. Originating from China, Taiwan, and Vietnam, this pest has since spread rapidly across the Northeastern United States, impacting states such as New Jersey, Maryland, New York, and Virginia. These insects pose a significant threat to agriculture and natural ecosystems by feeding on a wide array of plants, including grapevines, fruit trees, and various ornamental and woody trees. Understanding their seasonal patterns is important for managing their populations.
The Impact of Cold Weather
Adult spotted lanternflies largely succumb to the onset of cold weather, with the first hard frost acting as a primary environmental trigger for their mass die-off. Prolonged temperatures consistently below 28 degrees Fahrenheit are lethal to the adult lanternfly population. This die-off typically occurs in late autumn to early winter, spanning from September through November and sometimes into December, depending on when freezing conditions arrive. While some individuals might find temporary refuge, they eventually perish as sustained cold sets in.
The Lanternfly Life Cycle
The spotted lanternfly completes its life cycle within a single year, progressing through distinct stages from egg to adult. Eggs typically hatch into nymphs between April and June. These nymphs undergo four developmental stages, or instars, with the first three instars appearing black with white spots, and the fourth instar developing a red coloration with white spots. Adult lanternflies begin to emerge in July and can be observed through December. Mating commences in late August, leading to egg-laying activities from September until the first killing freeze.
What Happens to Their Eggs
Before adult spotted lanternflies die off, females lay resilient egg masses, typically from late summer through the first hard frosts. These masses appear grayish-brown, with a mud-like coating, and are approximately 1 to 1.5 inches long. Each mass can contain between 30 to 60 eggs, and a single female may lay one or two such masses. These eggs are commonly deposited on a wide variety of hard outdoor surfaces, including tree bark, rocks, outdoor furniture, vehicles, and firewood. The eggs are notably hardy and overwinter, hatching the following spring to continue the cycle, even surviving temperatures as low as -27.7 degrees Celsius in some cases.