Tree Spraying for Emerging Invasive Pests
Invasive pests pose an ongoing threat to trees across Long Island. Global trade, warmer temperatures, and changes in land use have facilitated the movement and establishment of insects and pathogens outside their native ranges. Once introduced, these organisms often flourish in their new environment because they lack natural predators. The emerald ash borer, spotted lanternfly, and spongy moth are just a few examples of invasive species currently challenging tree health on Long Island. Tree spraying is one of the tools available to manage these pests, but it must be applied thoughtfully and in conjunction with other practices. This article discusses emerging invasive pests, the signs of infestation, and the role of tree spraying in protecting your trees.
The emerald ash borer is a beetle native to Asia that has devastated ash trees across much of the United States. Adult beetles lay eggs in the crevices of ash tree bark. When the larvae hatch, they bore into the cambium layer, disrupting the transport of water and nutrients. Early signs of infestation include thinning canopies, D‑shaped exit holes in the bark, and serpentine galleries beneath the bark. Because infestation is often fatal if untreated, timely intervention is crucial. Tree spraying can help control emerald ash borer populations when applied as a systemic insecticide that the tree absorbs. Injections or soil drenches deliver the active ingredients directly to the cambium, where larvae feed. This targeted approach minimizes environmental impact and provides season‑long protection.
The spotted lanternfly, first discovered in Pennsylvania in 2014, feeds on a wide variety of trees and plants, including grapes, fruit trees, and maples. They use their piercing mouthparts to suck sap from stems and leaves, excreting a sticky substance called honeydew that promotes sooty mold growth. Signs of infestation include oozing wounds on tree trunks and branches, large congregations of insects, and blackened bark. The spotted lanternfly also lays egg masses on almost any smooth surface, including vehicles and outdoor furniture, making their spread difficult to contain. Tree spraying can reduce lanternfly populations by targeting the nymph and adult stages. Foliar applications may be used for contact control, while systemic treatments provide extended protection. Removing tree of heaven, the lanternfly’s preferred host, and banding trees to trap nymphs are additional measures that complement spraying.
Spongy moth, previously known as gypsy moth, is another invasive pest that defoliates hardwood trees such as oak, birch, and willow. Caterpillars emerge in late spring and feed voraciously on foliage, sometimes stripping entire trees bare. While healthy trees can survive one year of defoliation, repeated attacks weaken them and make them susceptible to diseases and other pests. Biological pesticides containing Bacillus thuringiensis var. kurstaki can be sprayed on foliage to control spongy moth larvae. The application must coincide with the early larval stages for maximum effectiveness. Other emerging pests include Asian longhorned beetle, which attacks maples and other hardwoods by tunneling into the heartwood, and hemlock woolly adelgid, which feeds on hemlock needles. Each pest requires a specific management strategy, and professional guidance is essential for proper identification and treatment.
Tree spraying is most effective when integrated with other control methods. Sanitation practices, such as removing infested trees and properly disposing of firewood, help prevent the spread of pests. Biological controls, including releasing natural predators or parasitoids, can suppress pest populations. Cultural practices, such as diversifying plantings and maintaining tree vigor through proper watering and fertilization, increase resistance to pests. Regular monitoring of trees for signs of infestation allows early detection and rapid response. Working with a professional arborist ensures that treatments are timed correctly and that the most appropriate products are used. They will also consider factors such as proximity to water bodies, wildlife, and pollinators, ensuring that spraying is done responsibly.
Emerging invasive pests will continue to challenge tree health on Long Island. Staying informed about these species and taking proactive measures is essential for protecting your trees and the broader environment. Tree spraying can be an effective tool when used as part of a comprehensive management plan. Consult with professionals to identify pests accurately, evaluate the risks, and determine the best course of action for your property. By combining knowledge with action, we can limit the impact of invasive pests and preserve the green canopy of our communities.
