Spotted Lanternflies (SLF) are an invasive insect species known for feeding on plants and trees, causing damage and leaving behind sticky residue. While adult lanternflies die when freezing temperatures arrive, the species survives the winter exclusively in the egg stage. This annual cycle makes winter a unique and important time for controlling the population.
The Fate of the Adult Lanternfly
The adult life stage of the Spotted Lanternfly is not designed to withstand cold weather. These insects mature in late summer and are active through the fall, but they lack the biological mechanisms to survive freezing temperatures. Their lifespan concludes after they have mated and the females have deposited their egg masses.
The death of the adults is typically triggered by the first hard freeze of the season, usually occurring between November and December in infested regions. While some may persist in sheltered areas slightly longer, the overall population of flying insects is eliminated by the onset of deep winter. This die-off creates a temporary pause in the active feeding and movement of the pest, offering a window for management efforts.
The Overwintering Stage
The survival of the Spotted Lanternfly through winter depends entirely on its egg masses, which are highly protected from the cold. Female lanternflies lay these masses, each containing 30 to 60 eggs, on a wide variety of outdoor surfaces. They can be found on tree trunks, stone, outdoor furniture, grills, utility poles, and vehicles.
The egg masses are covered with a protective layer of waxy secretion that helps insulate them from the elements. When first laid, this covering is a creamy-white, putty-like substance that gradually dries and turns a pinkish-gray color. As the mass ages through the winter, it darkens to a dull, cracked tan, often resembling a smear of dried mud or plaster.
This protective coating allows the eggs to remain viable even when exposed to frigid winter conditions. Because the egg masses can be laid on nearly any hard surface, they are easily transported inadvertently by people moving firewood, outdoor equipment, or vehicles. These hardy masses are the sole source of the next year’s infestation.
Timing and Transition
The period between late fall and early spring is the most effective time for control efforts, as the Spotted Lanternfly is concentrated in its immobile egg stage. The control window begins after the adults have died off and finished laying eggs, extending until the eggs begin to hatch in spring. This period allows for the targeted manual removal of the next generation.
Hatching is dependent on rising regional temperatures and typically begins in mid-to-late April, continuing into May. Before this emergence, control efforts focus on scraping the egg masses off surfaces and destroying them, often by placing them into a bag with hand sanitizer or alcohol. Removing these masses is a direct way to reduce the number of nymphs that will emerge and start feeding in the warmer months.