The Spotted Lanternfly (Lycorma delicatula) is an invasive planthopper from Asia that poses a significant threat to agricultural crops and woody ornamentals across the United States. This pest feeds on the sap of over 70 plant species, including grapes, hops, and hardwoods, weakening them and excreting a sticky “honeydew” that promotes the growth of sooty mold. Controlling this destructive insect relies heavily on targeting the flightless, highly mobile nymph stage before they mature into adults, which can lay hundreds of overwintering eggs. Successful management requires a multi-pronged approach utilizing both physical and chemical methods to suppress populations and limit their spread.
Identifying Nymph Stages and Prime Control Timing
The Spotted Lanternfly undergoes four distinct nymphal stages, known as instars, which represent the optimal window for control. The first three instars, active from late April or May through July, are small, black insects covered in bright white spots. These early-stage nymphs are less than a quarter-inch long and often move in clusters on new, tender plant growth, making them easier to spot and eliminate.
The fourth and final instar appears from July through September, marking a dramatic change in appearance. These nymphs are noticeably larger, growing up to a half-inch long, and display a vibrant red coloration in addition to the black and white spots. Targeting this stage prevents females from laying new egg masses. Control is most effective during this phase because nymphs must crawl up and down host trees to feed.
Hands-On Physical Removal Techniques
Direct, manual action is an immediate and environmentally sound way to eliminate Spotted Lanternfly nymphs. The simplest method involves crushing or squishing any nymphs encountered, especially when they are clustered. This technique requires no specialized tools and ensures the pest is destroyed instantly.
For larger concentrations of nymphs, a shop vacuum can quickly capture them from tree trunks or other surfaces. To ensure the collected insects are killed, the vacuum canister should contain a small amount of soapy water, or the contents should be sealed and left for 24 to 48 hours before disposal.
Specialized circle traps or sticky bands can also be installed around the trunks of host trees. These traps intercept nymphs as they crawl up the tree to feed in the canopy, and they are most effective when installed as early as May to capture the first instars. If using sticky bands, cover the adhesive surface with a barrier (like window screening or wire mesh) to prevent the accidental capture of beneficial insects and small animals. The trap material should be secured tightly to the tree trunk about four feet from the ground to maximize effectiveness.
Using Low-Toxicity Contact Sprays
Low-toxicity contact sprays offer control without harsh, long-lasting chemicals. Insecticidal soaps and horticultural oils, such as neem oil, are effective against nymphs and are less harmful to beneficial insects than many synthetic options. These products work by disrupting the insect’s outer cuticle or by suffocating them, meaning the spray must physically coat the nymph to be lethal.
Insecticidal soaps are often mixed at about one percent (e.g., three ounces of soap per thirty ounces of water). When applying these sprays, thorough coverage is necessary, and they should be used as a spot treatment directly on clusters of nymphs. Avoid spraying during the heat of the midday sun, as this can increase the risk of phytotoxicity, or damage to the plant’s foliage.
These low-residual products break down quickly, meaning they do not continue to kill insects after the spray has dried. Repeated applications may be needed throughout the season as new nymphs emerge or migrate into the area. To protect pollinators, these contact sprays must never be applied to plants that are currently blooming.
Chemical Insecticide Applications
For severe infestations or when nymphs are high in the tree canopy, chemical controls may be necessary, requiring careful application and adherence to all label instructions. Insecticide options include contact and systemic treatments. Contact insecticides, such as products containing pyrethrins, bifenthrin, or beta-cyfluthrin, kill nymphs upon direct exposure.
These are applied as a spray to the tree bark, branches, or foliage, and they provide residual activity, continuing to kill pests after the initial application. Systemic insecticides (e.g., imidacloprid and dinotefuran) are absorbed by the tree and move through its vascular system. When nymphs feed on the sap of a treated tree, they ingest the toxin and die, offering weeks or months of protection.
Systemic treatments are applied as a soil drench around the base of the tree or via trunk injection. Specific products are recommended at different times of the year to protect pollinators. Due to the complexity of application and potential for non-target impact, homeowners should consult a certified arborist or licensed pesticide applicator for systemic treatments. Always wear appropriate safety gear, restrict applications near food crops, and verify that the chosen product is approved for use against Spotted Lanternflies in your state.