Garden: Spotted lanternfly spreads in Greater Columbus

Spotted lanternfly (SLF), Lycorma delicatula, is an invasive planthopper which is native to Asia and was first detected in North America in 2014 in southeastern Pennsylvania.

The pest has now spread to other states in the eastern and Midwestern U.S. and was first detected in Ohio near the West Virginia border in the fall of 2020, and infestations of the pest have now been found in 11 Ohio counties.

The pest was first detected in Franklin County last summer, and in the past week, infestations of the pest have been found in numerous locations in Greater Columbus, a clear indication that the pest has become established in our area.

Spotted lanternfly feeds voraciously on several economically important crops, such as grapevines, hops, ornamental-landscape plants and trees. Heavy infestations of this insect have contributed to the death of grapevines.

SLF feeding can stress plants and cause localized branch damage but is not known to directly kill other plants. Feeding by SLF is considered a plant stressor and may contribute to the long-term weakening of established plants and trees by other insects, diseases or cultural factors, such as drought. It is currently considered primarily a nuisance pest in residential landscapes.

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Host plants

The invasive tree of heaven, Ailanthus altissima, is the primary host of the spotted lanternfly. Tree of heaven is an invasive species which grows in unmanaged areas, such as rights-of-way along railroad tracks, highways and alleys in urban neighborhoods.

Many of the initial finds of this insect, including the first find in Columbus, have been found on trees of heaven in these types of locations. A secondary host plant for SLF is black walnut saplings and both host plants are killed by the pest.

Life cycle

There is one generation of SLF per year, with eggs laid in the fall from September through December. Eggs hatch in the spring from April through June. Egg masses are laid on vertical surfaces, such as trees, utility poles, decks, rocks, outdoor equipment, etc., and are protected with a mud-like covering. Each egg mass can contain up to 35 individual eggs.

After hatching and before reaching adulthood, SLF goes through four nymphal stages called instars. Most of the SLF instars found last week in Greater Columbus were in the second and third instar stages.

In the first three instar stages, the insect is black with white spots. In the final instar stage, the insect is red with white spots and black stripes and measures about 1/2-inch long. The insect is much smaller in the first three instar stages and can easily be mistaken for a tick in these stages.

The adult SLF is the most obvious and easily detectable stage because they are large, about 1 inch, and very mobile. Adults have black abdomens with yellow bands. The wings of the adult SLF are very colorful with splashes of red, tan and grey with distinctive black spots. Only the adult stage of SLF has wings and can fly.

Feeding damage

Spotted lanternfly feed on plant sap using piercing-sucking mouthparts. They acquire nutrients from the sap which contains high amounts of sugar, which is not completely digested by the insect. They excrete the excess as a liquid-waste substance called honeydew, which can be seen dripping down the trunks of host plants.

This honeydew is attractive to ants, wasps, bees and other sugar-loving insects, so many times, these other insects can be found congregating and feeding on plants infested with SLF.

As honeydew accumulates, it is often colonized by a sooty mold fungus. While this fungus does not directly harm plants, it physically covers the surface of leaves, reducing photosynthesis and causing the plant to die.

The only plants known to be killed by SLF are trees of heaven, walnut saplings, grapevines and hops, although feeding by SLF has been documented on more than one hundred different plant species.

Controlling the spread

Gardeners in Greater Columbus should be scouting for the nymphal stages of SLF right now, particularly in areas close to where tree of heaven is found growing. Locations close to railroad tracks, highways and other areas with unmanaged vegetation should be closely monitored for presence of the insect.

Tree of heaven is an invasive plant which should be removed by property owners, even if it is not currently infested with SLF.

The nymphal stage of SLF can feed on vegetable, fruit and herb plants, but plants are only damaged when very high populations of the pest are present on these plants. Feeding by SLF is most common on cucumber, basil, horseradish, raspberry and asparagus. The presence of dripping honeydew or the black sooty-mold growth on a plant are a red flag which requires close inspection and monitoring.

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If you find spotted lanternfly on your property, document the find with a photo and send the information to the Ohio Department of Agriculture (ODA) at go.osu.edu/reportSLF.

Because the presence of SLF has already been documented in Franklin County and a quarantine exists for this pest in the county, ODA will likely not inspect every new site where the pest is reported to be found.

Once you document the presence of SLF, you can destroy the insects. While some pesticides are likely effective in killing SLF, many pesticides also kill beneficial insects in the environment, so their use should be minimized

Physical removal and destruction of both nymphs and adult stages of SLF is simple and practical. Simply swat the pests into a bucket of soapy water and dispose of them. Applications of pesticides, such as less toxic insecticidal soaps and oils, can also be effective in controlling SLF nymphs at this time.

Later this fall and winter, areas near known infestations should be monitored for egg masses and the egg masses should be scraped from the surface where they have been laid into a bucket containing rubbing alcohol and disposed of.

In the fall and winter, SLF will lay eggs on trees on which they typically do not feed, as well as on lawn furniture, decks, posts and other surfaces.

Mike Hogan is Extension Educator, Agriculture and Natural Resources and associate professor with Ohio State University Extension.

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This article originally appeared on The Columbus Dispatch: Garden: What to know about spotted lanternfly in your garden