d. Contact insecticides kill SLF when the chemical contacts the insect as a direct spray or when the insect walks over a surface with insecticide residue on it. Systemic insecticides are absorbed by tree roots, bark, or leaves and are moved through its vascular system to other parts of the tree. When systemic insecticides are used, SLF is killed as it feeds on any part of the tree, even if it was not sprayed directly (e.g., spraying the lower part of the tree will protect the tree tops). Systemic insecticides work best when applied from July-September. However, systemics can also be applied at other times of year, depending on the application method. For example, a soil drench should be applied earlier in the summer.
There are four main methods to apply insecticides: tree injection (applied by professional applicators), bark sprays, soil drenches, and direct sprays (can be applied by homeowners). The Pennsylvania Department of Agriculture and the U.S. Department of Agriculture are currently using the systemic insecticide dinotefuran as bark sprays on tree-of-heaven to kill SLF. Systemic insecticides can work well and have residual activity that lasts from several weeks to several months. Property owners should consider hiring a certified pesticide applicator to make insecticide applications. Professional applicators have specialized training and equipment to treat trees. Hiring a professional may reduce your risk of pesticide exposure and save time, but it may cost more than doing the application yourself.
||Mode of Exposure
||Activity Against SLF
||ornamental and landscape plants and trees
||Garden Tech Sevin Ready-to-Spray Bug Killer (note: new formulation is sold with zeta-cypermethrin)
||vegetable and ornamental plants and trees under 10 feet tall
||Safari 20SG, Transect 70 WSP, Zylam Liquid
||ornamental and landscape plants and trees
||Bayer Advanced 3 in 1 Insect Disease
Mite Control, Bonide Annual Tree &
Shrub Insect Control
|ornamental and landscape plants and trees
||Garden Safe Insecticidal Soap
||vegetables, fruit trees, ornamentals, shrubs, flowers, and gardens
||Spectracide Malathion Insect Spray
||flowers and bushes, fruit, and vegetables
||Garden Safe Multi-Purpose Garden Insect Killer, Natria Insect Mite and Disease Control
||vegetables, ornamentals, trees, shrubs, and flowers
||Bonide Neem Oil
||flowers, ornamental trees and shrubs, fruit, nuts, and vegetables
||Bonide Captain Jack’s Deadbug Brew
||outdoor ornamentals, fruit, and vegetables
||BioAdvance 3 in 1, Insect, Disease and Mite Control
||nonedible plants only, groundcovers, vines, ornamentals, shrubs, and trees
||Amdro Quick Kill Outdoor Insect Killer Concentrate
||lawns, trees and shrubs, roses, and flowers
*Recommended for organic production.
Note: The listing of products in this table is not an endorsement or specific recommendation of the product or the company. Other products with the same active ingredient should also work in the same way, but they may have different rates or formulations.
Some insecticides available at your local garden or hardware store can be used as soil drenches, bark sprays, or direct sprays. Direct sprays of contact insecticides are applied to surfaces where SLF feeds and walks, which can include the base of a tree, such as tree-of-heaven, where spotted lanternflies are abundant. They can also be applied directly to SLF nymphs and adults. Systemic insecticides can be applied using any of the methods above, but keep in mind that systemics take time to move into the tree. Systemic pesticides should only be applied to trees actively growing, so they should not be applied in late fall or winter. You may apply systemic insecticides using a soil drench around the base of the tree, as a bark spray on the trunk of the tree, or as a direct spray on the leaves of the tree. Systemic insecticides can also be injected into a tree, but this requires special equipment by tree care professionals. Bark sprays have been shown to work well for SLF control, but some of these products also require being mixed with a penetrant, which allo