Penn. Campus


Spotted Lantern Fly at the University of Pennsylvania – We Need Your Help!

August 4, 2020
spotted lantern fly on wooden rail

This year, our region is experiencing a significant population increase of Spotted Lantern Fly (SLF), an invasive insect. Facilities and Real Estate Services (FRES), in partnership with Morris Arboretum, has developed a strategy to address this nuisance pest that has the potential to negatively impact over 70 different plant species.

FRES is working to remove and/or treat (when appropriate) the spotted lantern fly's favored host tree, Tree of heaven (Ailanthus altissima). Penn is following expert recommendations that suggest limiting the use of toxic chemicals that are ecologically damaging and would not greatly reduce SLF populations.  If you want to take action, the egg cases can be carefully scraped off in the winter, and killing the instars or adults by hand is challenging, but can slightly reduce local populations. 

Spotted lantern flies generally do not kill healthy trees, though they can cause significant damage on certain plants, particularly if they are already weakened. SLFs feeding on tree sap results in large amounts of honeydew (partially digested tree sap containing sugars) which allows sooty molds to grow under heavily infested trees, which can damage plants and result in cosmetic damage to infrastructure like cars, benches, etc. Furthermore, honeydew attracts stinging/biting insects, e.g. wasps and ants, which can be problematic for users at certain locations like benches or picnic areas.  

Please email us if you see honeydew AND it is creating an issue with hardscape usability because of stickiness, or an overabundance of wasps/ants at Please include the date and exact location of the problem.

Your information will allow us to craft a custom treatment program that will appropriately respond to this threat and limit the amount of pesticides used on campus. Thank you for your help.  

Visit the Penn State Extension website for more general information on spotted lantern flies. 

*Illustration courtesy of Colleen Witkowski, Penn State

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