ws the insecticide to penetrate the bark and move into the tree. There are penetrants available to homeowners, including Pentra-Bark. You must read the label of the insecticide you purchase to determine whether it should be used as a soil drench, bark spray, or direct spray.
Soil drenches of systemic insecticides are applied into the soil around the trunk of the tree. The insecticide is taken up by the roots and moved into the rest of the tree. Ideally, soil drenches work best when applied in the early summer to trees that had high SLF populations in the past and are likely to have them again. To protect pollinators, soil drenches of systemic insecticides should be applied after a tree’s flowers have faded. Soil drenches and bark sprays may take several days or weeks to move within the entire tree, so you should not expect immediate results, as with contact sprays. Depending on the product and rates used, soil drenches, bark sprays, and injections have the advantage of longer residual activity (several weeks to several months) over contact insecticide applications.
In the table on the previous page, the name of the product is listed, along with the mode of exposure, legal use, activity ranking against SLF, and residual activity (how long it stays active). Specific products listed are not an endorsement. Please note that most currently available products are not registered for use on SLF. It is legal to use them as long as you follow the label instructions, but these products and/or their manufacturers are not liable for results when used against SLF. Research is ongoing to identify the insecticides that are most effective on SLF while posing the least risk to humans, pets, beneficial insects, and the environment. Additional field trials are being conducted to test the efficacy and residual activity of a wider range of the insecticides that are available to homeowners. We have not yet evaluated nontarget effects of listed insecticides on beneficial insects, including pollinators. We do not recommend treating your entire property since these insecticides are not specific to SLF and beneficial insects may be affected as well. Only treat areas where SLF is abundant.
These recommendations are current as of March 18, 2019, and may change as we learn more. We encourage you to stay up to date by visiting our website. Check the version of this fact sheet and always look for the most up-to-date information. When using any pesticide, follow the pesticide label for directions, application rates, methods, and appropriate protective equipment.
Prepared by Heather Leach, spotted lanternfly extension associate; David Biddinger, tree fruit research entomologist and research professor; and Greg Krawczyk, extension tree fruit entomologist and research professor.
This fact sheet was produced by Penn State Extension in collaboration with the Pennsylvania Department of Agriculture and the United States Department of Agriculture.