Will homemade sprays stop spotted red lantern insects? - Ask Extension
Hello! Our landscape company for our community association says they can spray something at the base of the trees that will kill these insects if they...
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Will homemade sprays stop spotted red lantern insects? #876686
Asked July 10, 2024, 2:08 PM EDT
Hello! Our landscape company for our community association says they can spray something at the base of the trees that will kill these insects if they eat the bark. But they also say it would kill beneficial insects.
Will homemade sprays do the trick ? Will people have to do it all season long?
Thanks,
Kathleen
Landscape chairperson
Howard County Maryland
Expert Response
Hello Kathleen,
Basal bark sprays of insecticide tend to involve ingredients in the chemical group called pyrethroids. They are synthetic versions of pyrethrin (a naturally-derived chemical) that are designed to last longer and not degrade as quickly into residues that become ineffective. The consequence of that is a greater exposure risk to harmless and beneficial insects and other organisms. Pyrethroids are broad-spectrum pesticides, meaning they are not very limited in their impacts; they will not kill only the targeted pest(s). They can indeed work well for pest control, but since they are one of the higher-risk insecticides with regards to unintended impacts, we do not recommend their use for most situations, including this one.
With several years of observations and studies having taken place since this insect first arrived in our area, Spotted Lanternfly (SLF) is not known to cause any serious damage to home garden and landscape plants, including shade trees and flowering trees. Because of this, no treatment is necessary. Additionally, no insecticide, organic or otherwise, is specific to SLF where it will not pose some risk of harm to pollinators, beneficial insects, or other wildlife that come into contact with its residues. If a tree where SLF is aggregating happens to be a Tree of Heaven, then its removal is recommended because it's an invasive species, but otherwise other tree species should be fine without intervention.
SLF is not eating bark; they can only suck sap (through the bark or a plant stem, but the pinprick injury generated by their straw-like mouthparts is inconsequential). If there is visible bark damage on a tree with SLF presence, or branch dieback, premature leaf shedding, or other significant symptoms of concern, that damage was caused by some other issue.
Home remedy insecticides are not a good idea and we do not recommend them. Penn State has a good article explaining some of the risks of their use (see the linked page). In short, they either don't work well or consistently well, and/or may actually risk causing worse problems (damaging the plant, causing environmental harm, or injuring the plant more than the pest itself was).
The main issue with SLF when concentrations of them are large is the nuisance (and when it ferments, the objectionable odor) of honeydew they produce as a waste product, plus the sooty mold that might grow on top of those residues (which can cover plants, but does not cause disease). Essentially sugar-water, honeydew can rinse off of plants and other surfaces relatively easily, so it doesn't build-up as badly, but in years with drought, accumulation is more likely. Honeydew-coated surfaces can be rinsed off periodically, but eventually both it and any sooty mold will weather off on its own. Not every area with some SLF will have this problem, just certain spots where high numbers of the insects (adults, usually) are congregating, like on Tree of Heaven trunks.
Miri
Basal bark sprays of insecticide tend to involve ingredients in the chemical group called pyrethroids. They are synthetic versions of pyrethrin (a naturally-derived chemical) that are designed to last longer and not degrade as quickly into residues that become ineffective. The consequence of that is a greater exposure risk to harmless and beneficial insects and other organisms. Pyrethroids are broad-spectrum pesticides, meaning they are not very limited in their impacts; they will not kill only the targeted pest(s). They can indeed work well for pest control, but since they are one of the higher-risk insecticides with regards to unintended impacts, we do not recommend their use for most situations, including this one.
With several years of observations and studies having taken place since this insect first arrived in our area, Spotted Lanternfly (SLF) is not known to cause any serious damage to home garden and landscape plants, including shade trees and flowering trees. Because of this, no treatment is necessary. Additionally, no insecticide, organic or otherwise, is specific to SLF where it will not pose some risk of harm to pollinators, beneficial insects, or other wildlife that come into contact with its residues. If a tree where SLF is aggregating happens to be a Tree of Heaven, then its removal is recommended because it's an invasive species, but otherwise other tree species should be fine without intervention.
SLF is not eating bark; they can only suck sap (through the bark or a plant stem, but the pinprick injury generated by their straw-like mouthparts is inconsequential). If there is visible bark damage on a tree with SLF presence, or branch dieback, premature leaf shedding, or other significant symptoms of concern, that damage was caused by some other issue.
Home remedy insecticides are not a good idea and we do not recommend them. Penn State has a good article explaining some of the risks of their use (see the linked page). In short, they either don't work well or consistently well, and/or may actually risk causing worse problems (damaging the plant, causing environmental harm, or injuring the plant more than the pest itself was).
The main issue with SLF when concentrations of them are large is the nuisance (and when it ferments, the objectionable odor) of honeydew they produce as a waste product, plus the sooty mold that might grow on top of those residues (which can cover plants, but does not cause disease). Essentially sugar-water, honeydew can rinse off of plants and other surfaces relatively easily, so it doesn't build-up as badly, but in years with drought, accumulation is more likely. Honeydew-coated surfaces can be rinsed off periodically, but eventually both it and any sooty mold will weather off on its own. Not every area with some SLF will have this problem, just certain spots where high numbers of the insects (adults, usually) are congregating, like on Tree of Heaven trunks.
Miri
