Spotted Lanternfly and Tree of Heaven—Invasive Begets Invasive

Spotted lanternfly (SLF for short) is a destructive sap-feeding planthopper. SLF is a relatively new plant pest to the United States. While just two small populations were verified in Fairfield County in 2020, it is now found across CT and widespread in Fairfield and New Haven counties.
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A pretty distinctive insect, adults are about one inch long and a half inch wide. Their forewings are tan with black spots. Hindwings, noticeable when wings are spread, are colorful red and black patches separated by a white patch. Adults are active from July to November and will crawl, jump, or fly short distances. ​

Invasive Tree of Heaven (Ailanthus altissima) is the preferred food source (host plant) for the spotted lanternfly. This rapidly growing deciduous tree has become a widespread invasive species across North America. Also known as stinking sumac or Chinese sumac, it was introduced to the U.S. as a horticultural specimen and shade tree. Rapid growth and abundant seeds allow it to spread aggressively to create dense thickets that displace native vegetation. It also secretes a chemical into the soil that is toxic to surrounding plants.

While spotted lanternfly is attracted to tree of heaven, it also feeds on economically important plants including grapevines, ornamentals, and native trees such maple, black walnut, birch and willow. Feeding damage significantly stresses plants, impacting health with potential for causing death. For additional information, go to the Connecticut Agricultural Experiment Station and search: spotted lanternfly.

Protect your property and trees. The CT Agricultural Experiment Station says the best thing a homeowner can do is rid your property of Tree of Heaven, so not to attract spotted lanternfly. Local arborist, Mike Switser of North Country LLC, is fully licensed with expertise in proper management.

How to Identify Tree of Heaven
It is important to correctly identify the tree of heaven. On first glance, it appears similar to some native trees and shrubs that also have leaves arranged in pairs along a plant’s stem (staghorn sumac, hickory and black walnut). TOH is distinguished by a notch at the base of each leaf, fuzzy, reddish-brown twigs, and clusters of light green seed pods. If all else fails, there is the unmistakably strong, offensive smell to its flowers, leaves and stems when crushed, resembling burnt peanut butter.

A multiple threat. If displacing native vegetation, threatening natural ecosystems, and attracting a destructive pest isn’t harmful enough, tree of heaven with its aggressive root system can also damage pavement, sewers and wells, and building foundations. 

Controlling Tree of Heaven
According to the Penn State Extension, cutting alone will not reduce tree of heaven’s ability to spread, in fact, it could make it worse. Pulling TOH out can also activate the root system, causing it to send up more shoots to create new trees. The best method is to target the roots with a systemic herbicide applied mid-to-late summer until onset of fall color when the tree is moving carbohydrates to the roots. Herbicides can be applied to foliage, bark, or cuts on the stem, also known as hack and squirt. However, cut stump herbicide applications do not prevent root suckering and should not be utilized. Herbicide applications made outside this late growing season window will only injure above ground growth. As always, employing the help of a professional licensed pesticide applicator is recommended. For more information, watch Penn State Extension's guide for controlling Tree of Heaven.

The Newtown Conservation Commission is actively working to encourage healthy habitats and increase the diversity of our native wildlife and vegetation. www.newtownconservation.org