The Spotted Lanternfly (SLF) is a highly destructive invasive insect that threatens agricultural crops and forests. This pest causes damage by feeding on plant sap and excreting honeydew, which fosters the growth of black sooty mold. Controlling the spread of this insect is most effectively achieved by locating and destroying its egg masses. These masses are laid from late summer through fall, survive the winter, and represent the pest’s only stationary life stage, making their elimination crucial for limiting the next generation’s population.
The Anatomy of an Egg Mass
A Spotted Lanternfly egg mass is typically an oblong patch, measuring about one to one-and-a-half inches long. Each mass is laid in rows and contains between 30 and 50 individual eggs, roughly the size of a sharpened pencil point.
When freshly laid, the female covers the eggs with a protective, waxy substance that is initially white and glossy. This covering quickly dries to a gray or tan color, taking on a putty-like or cement-like appearance similar to a smear of dried mud. As the mass weathers, the covering may crack or flake away, exposing the rows of small, seed-like eggs nestled together. If the eggs have already hatched, tiny oval-shaped emergence holes will be visible on the exposed remnants.
Common Hiding Spots and Surfaces
SLF females are not selective about where they deposit their eggs and will utilize nearly any flat, hard surface. This non-selective laying behavior makes thorough inspection necessary across a wide range of materials.
The masses are frequently found on the bark of trees, particularly smooth-barked species like maple and river birch, as well as the invasive Tree of Heaven, a preferred host plant. Females often choose protected areas such as the undersides of tree limbs, branch crotches, and surfaces angled toward the ground. However, the most significant risk for long-distance spread comes from eggs laid on movable, human-made items.
SLF will lay eggs on stationary outdoor equipment, including grills, patio furniture, and stone or brick walls. It is particularly important to inspect items that may be transported, such as vehicles, trailers, RVs, firewood, outdoor machinery, shipping containers, and pallets, to prevent accidental movement of the invasive pest.
Distinguishing Look-Alikes
Accurate identification is important to avoid destroying beneficial native insect egg masses. The distinctive putty-like covering of a fresh SLF mass is a primary identifying feature that separates it from many other common objects.
Common Look-Alikes
- Lichen: Patches of lichen are typically thinner, flatter, and more irregular in shape and texture than the SLF mass.
- Spongy Moth Egg Mass: This mass is covered with a thick layer of tan or buff-colored, felt-like hairs, a texture entirely absent from the smooth, mud-like SLF covering.
- Praying Mantis Oothecae: Mantis egg cases are much larger, lighter in color, and have a foamier, layered, and ribbed texture that hardens into a lightweight shell, unlike the dense, flat SLF mass.
- Mud Dauber Wasp Nests: These nests are made of durable, hardened mud, but they form a distinct, cylindrical structure with an open cavity inside, contrasting with the flat, smear-like appearance of the lanternfly egg mass.
Action After Identification
Once a Spotted Lanternfly egg mass is positively identified, it must be destroyed immediately to prevent hatching. The most effective method is physical removal and disposal. Use a hard, flat implement, such as a plastic credit card, a putty knife, or a paint scraper, to scrape the mass completely off the surface.
The scraped material must then be placed into a sealed container or a resealable plastic bag filled with rubbing alcohol or hand sanitizer. The alcohol is necessary to ensure the eggs are killed, as simply scraping them onto the ground may not be sufficient to prevent hatching. Keep the container sealed and dispose of the contents in the trash. If the sighting is outside of a known quarantine or infested zone, take a photograph and report the location to the local agricultural extension or state department of agriculture before destruction.