The Spotted Lanternfly (SLF) is an invasive insect that poses a significant threat to agricultural crops and various hardwood trees across the United States. Control efforts are most effective when focused on the egg stage, as a single mass contains dozens of future pests. Targeting the eggs prevents the next generation from hatching and beginning its destructive life cycle. Because the egg masses are stationary and unable to escape, they present the most accessible and vulnerable stage for elimination.
Locating and Identifying Egg Masses
Spotted Lanternfly females lay their eggs in the late summer and fall, and these masses remain dormant throughout the winter until they hatch, typically by May. Each egg mass is relatively small, often measuring about one to one-and-a-half inches long. They are generally composed of 30 to 50 individual eggs deposited in neat, segmented rows.
Initially, a female covers the eggs with a protective, grayish-brown substance that looks like a smear of mud, dried clay, or an uneven patch of mortar. This waxy coating helps camouflage the eggs. Eggs can be found on nearly any outdoor surface, from the smooth bark of trees like maple and willow to stone, rusty metal, picnic tables, and vehicles. Inspecting frequently moved items, such as firewood or outdoor equipment, is important to prevent accidental transport and spread.
Mechanical Removal Techniques
Scraping is the most direct and effective method for destroying egg masses that are within arm’s reach. To perform this, you will need a stiff, flat implement, such as a plastic gift card, a putty knife, or a paint scraper. The goal is not just to remove the mass but to ensure the eggs inside are crushed and neutralized.
Position the scraping tool firmly against the surface, just above the mass, and apply downward pressure to shear the eggs away. As you scrape, you should hear a subtle popping or crushing sound, which confirms that the eggs are being destroyed. Simply scraping the masses onto the ground is not recommended, as some eggs may survive and still hatch into nymphs.
A preferred method is to scrape the mass directly into a sealable plastic bag containing rubbing alcohol or hand sanitizer, which immediately kills the embryos. Alternatively, you can smash the mass on the surface with your tool, applying forceful, even pressure across its entire length to rupture the individual eggs. Ensure the destruction of every egg within the mass before moving on.
Applying Chemical Treatments
For masses that are located too high up on trees or in areas that are otherwise physically difficult to reach, chemical treatments provide an alternative method of control. Ovicides, products specifically designed to kill eggs, are typically applied from late fall through early spring while the masses are still dormant. The most common and widely recommended ovicides for homeowner use are dormant or horticultural oils.
These oils work by coating the egg mass and smothering the developing embryo inside, effectively blocking the necessary gas exchange. Studies have shown that horticultural oils applied at a concentration of at least three percent can kill up to 75 percent of treated eggs. Thorough coverage is necessary because the waxy, mud-like covering on the egg mass must be fully saturated for the oil to penetrate and be effective.
When using any chemical product, follow all directions and safety precautions listed on the pesticide label. This includes wearing proper protective equipment and ensuring the product is rated for use on egg masses. While chemical options offer a solution for inaccessible masses, mechanical scraping remains the more consistently effective method for masses that can be safely reached.
Proper Disposal and Follow-Up
Once an egg mass has been successfully scraped, the collected material must be properly disposed of to ensure no eggs survive. The scraped material should be immediately sealed inside a plastic bag containing rubbing alcohol or hand sanitizer. This guarantees the death of any remaining viable eggs.
The sealed bag must then be tightly closed and disposed of in the regular trash. Do not compost the material or throw it into yard waste, as the eggs may survive these environments. Following the initial removal, repeat inspections of surfaces should be conducted throughout the winter and early spring. Any object or vehicle being moved from an infested area should be thoroughly checked for masses to prevent the pest from spreading to new locations.