Spotted Lanternfly

[Lycorma delicatula (White)]

January 2019
Lori Spears, Extension Entomologist • Ann Mull, Extension Assistant

Quick Facts

  • Spotted lanternfly (SLF) is an invasive planthopper that was first detected in the U.S. in Pennsylvania in 2014, and is not known to occur in Utah.
  • Currently SLF is predominantly considered a nuisance pest, as it can congregate in large numbers in and around homes and structures. It neither bites nor stings.
  • SLF is also considered a plant stressor and can cause significant damage to hosts that are already stressed.
  • SLF attacks more than 100 host plants worldwide, including grapes, fruit trees, hops, and hardwood and ornamental trees. In its native China, its preferred host is tree-of-heaven (Ailanthus altissima). 
  • SLF uses a piercing-sucking mouthpart to feed on stems, leaves, and bark. It does not feed directly on fruit.
  • Extensive feeding results in wounds that ooze sap. The sap can combine with the lanternfly's sugary excrement and result in the growth of sooty mold, a gray-black fungus that can impact plant vigor and crop yield.
  • SLF can spread to new areas by the unintentional movement of egg masses on infested plant material and outdoor items. 

Spotted lanternfly adult with open wings
Fig. 1.
 Spotted lanternfly (SLF) adult.
Left image: Spotted lanternfly adults on tree trunk; right image: adult at rest.
Fig. 2. SLF adults crawling along a tree trunk (left); SLF adult at rest (right).

Spotted lanternfly (SLF) (Lycorma delicatula (White), Order Hemiptera, Family Fulgoridae) (Figs. 1-3) is a new invasive planthopper to North America. It is native to northern China and has spread to other parts of Asia, including Vietnam, Japan, and South Korea, where it is causing considerable damage to grape and peach (Shin et al. 2010; Lee et al. 2011, Simisky 2020). SLF was first detected in the U.S. in Pennsylvania in 2014, and a quarantine was enacted to control its spread. As of October 2020, SLF has also been reported in Connecticut, Delaware, Maine, Maryland, New Jersey, New York, Ohio, Virginia, West Virginia, and in Oregon, where one dead specimen was found in a nursery shipment of planters and ceramic pots from Pennsylvania. SLF is a quarantine pest and can restrict interstate movement of regulated articles (e.g., fruit, lumber, and firewood). Be certain you are not moving any life stage of SLF when traveling within or out of quarantine zones. SLF is not known to occur in Utah. If you suspect SLF in Utah, contact the Utah Plant Pest Diagnostic Lab.
Spotted lanternfly on tree trunk
Fig. 3. Spotted lanternfly adult on tree trunk.

Description

Adult SLF are about 1 inch (2.54 cm) long and ½ inch (1.27 cm) wide when at rest. Females are slightly larger than males. The head is black with a piercing-sucking mouthpart. The forewing (visible outer wing when resting) is gray with black spots; the wing tips have closely spaced reticulated black blocks outlined in gray (Fig 3). The hind wings, which are visible during flight, have striking red, black, and white patches. Legs are black, and the abdomen is yellow with broad black bands on the top and bottom surfaces.

Females lay 1-2 egg masses; each mass contains 30 to 50 eggs and is covered by a waxy substance roughly 1 inch (2.54 cm) long. Newly laid egg masses are white in color but turn brownish-gray and mud-like as they age (Fig. 4). Beneath the cover, the eggs are seed-like and deposited in 4-7 parallel rows (Fig. 4). Eggs are laid on any smooth surface that is at least 1 inch (2.54 cm) wide, including tree bark, landscaping stones, outdoor furniture, vehicles, railway cars, telephone poles and fence posts (Simisky 2018) (Fig. 5).

Nymphs (immature life stage) undergo 4 instars (Fig. 6). The first 3 instars are black with white spots. The 4th instar develops red patches in addition to the white and black coloration. Fully-winged adults develop after the 4th instar. Note that the boxelder bug (Boisea trivettata) and small milkweed bug (Lygaeus kalmii) have a similar appearance to the 4th instar SLF (Fig. 7).


Spotted lanternfly nymphs
Fig. 6. Nymphs undergo 4 instars (molts). The first 3 instars are black with white spots (left); the 4th instar is black and white with red patches (right). 

Spotted lanternfly adult and egg masses
Fig. 4. Female SLF adult with a newly laid egg mass (left); beneath the mud-like covering, seed-like eggs are laid in parallel rows (center); hatched SLF eggs with emergence holes (right).

Spotted lanternfly egg masses on a post and on a barrel.
Fig. 5.
SLF lay eggs on a wide variety of surfaces that include both natural and manmade surfaces, such as fence posts (left) and rusty barrels (right).

Spotted lanternfly lookalikes
Fig. 7. Boxelder bug (left, in various life stages) and small milkweed bug (right) are potential SLF lookalikes that commonly occur in Utah.

Plant Hosts

SLF are broad generalists that feed on more than 100 plant species worldwide, with over 50 occuring in North America, including grape, fruit trees (apple, peach, cherry, apricot, and plum), and hardwood and ornamental trees (e.g., maple, willow, birch, ash, walnut, poplar, sycamore, aspen, oak, linden, pine, lilac, serviceberry, sumac, and dogwood) (Dara et al. 2015, Porterfield 2020). Adult SLF show a strong host preference for tree-of-heaven (Ailanthus altissima), an invasive plant from China that is widely established in the U.S.

Damage Symptoms

SLF uses a piercing-sucking mouthpart tapped into the plant like a straw to suck sap from stems, leaves, and bark on branches and trunks. It does not feed directly on fruit. Some plants are more at risk than others, and plant death has been observed only in grapevine, tree-of-heaven, and some tree saplings (Leach et al. 2020). Branches highly infested with SLF (Fig. 8) may lose vigor, wilt, and die, and branch flagging and canopy dieback can occur (Leach et al. 2020). Extensive feeding by SLF results in weeping wounds that will leave a trail of sap along the bark (Fig. 9). As it feeds, SLF secretes large amounts of sugary excrement (called honeydew) that, along with sap from oozing wounds, can promote the growth of fungi such as sooty mold (Fig. 9). Sooty mold (a gray and black fungus) develops around the base of trees and branch crotches; it can coat leaf surfaces, interfere with photosynthesis, and negatively affect plant growth and crop yield. Note that the presence of sooty mold can be due to factors other than SLF. Heavy infestations of SLF can cause a buildup of honeydew on adjacent plants in the understory, and affected plants may emit a fermented odor when SLF is present. SLF is considered a nuisance pest, as it can congregate in large numbers in and around homes and structures (Fig. 10), and the honeydew can attract unwanted insects such as ants and wasps, and coat items underneath affected trees (e.g., porches and vehicles) with the sticky residue. 

Spotted lanternfly adults on apple and grape. Fig. 8. Apple (left) and grape (right) highly infested with adult SLF.

Sooty mold at base of tree and adult spotted lanternfly on trunk Fig. 9. SLF feeding can result in weeping wounds and sooty mold growth (gray and black fungus on lower tree trunk). 

A mass of adult spotted lanternfly covering tree trunk in a yardFig. 10. SLF can congregate in large numbers and be a nuisance pest. 

Life History

SLF has one generation per year, and overwinters as eggs. Eggs are capable of surviving temperatures of around 12 °F (-11 °C) (Lee et al. 2014), and hatch from late April to early summer. Nymphs then begin crawling and feeding on the sap of a wide range of host plants. Nymphs, especially younger nymphs, engage in a cyclic behavior in which they repeatedly ascend and then fall from the tree after being disturbed by wind or other physical forces (Kim et al. 2011). This behavior may be due to less developed tarsal adhesive pads, which allow them to hold onto surfaces more firmly, or as a means of host selection and dispersal (Kim et al. 2011; Dara 2014). Adults are present by mid-summer (mid to late July) and appear to feed on only a few hosts, including tree-of-heaven. Since females are not reproductively mature at emergence, they must feed before mating. Eggs are laid from September to the onset of winter (late November to early December). Each female can produce 1 to 2 egg masses (30-100 total eggs). Adults die with a hard frost.

Monitoring

SLF can be monitored with visual inspection. Nymphs and adults gather in large numbers on host plants and are easy to find at dusk or night when they move up and down tree trunks. During the day, they tend to congregate in the canopy or at the base of the host plant if there is adequate cover. Begin monitoring for nymphs toward late April or early May, and then continue monitoring for adults through the summer and fall. In addition, keep an eye out for the mud-like egg cases on any smooth surface from September through April. Some research has examined the use of attractants and repellents for monitoring (and control) purposes. Possible attractants include spearmint oil and a methanol extract; possible repellents include lavender oil (Choi et al. 2012; Dara et al. 2015). 

Management

SLF has NOT been detected in Utah, so there is no current need for control of this insect. The management options listed below are provided should this pest be detected in Utah in the future. If you suspect SLF in Utah, contact the Utah Plant Pest Diagnostic Lab.

Non-Chemical Control 

Egg Mass Scraping

Egg cases can be scraped off a substrate by using a credit card, putty knife, or similar tool. Using a downward motion, scrape the egg mass into a vial containing rubbing alcohol or hand sanitizer and tightly seal (Fig. 12). 

Host Plant Reduction/Removal

Consider removing the invasive tree-of-heaven (Ailanthus altissima) if it is present on your property. Tree-of-heaven is the preferred host of SLF, but it is not as common in Utah as it is in the eastern U.S. In Pennsylvania, it is recommended to remove female tree-of-heaven, while leaving a few male “trap” trees for targeted insecticide sprays. Male trap trees are preferred over female trees because females produce seeds which can repopulate the property. Further, an herbicide application may need to accompany tree-of-heaven removal, as small pieces of remaining root can generate new shoots. For more information about managing tree-of-heaven, refer to USDA Forest Service Field Guide for Managing Tree-of-Heaven in the Southwest.

Sticky trap usage

Sticky traps for SLF should be reserved for when this pest is seen on trees, as bycatch such as birds, small mammals, lizards, and pollinators can be inadvertently trapped and killed. As SLF has not been detected in Utah, sticky traps should not be used for SLF at this time.

 



scraping slf egg masses into a container
Fig 11. Scrape SLF egg masses into a container filled with rubbing alcohol or hand sanitizer and tightly seal.

Biological Control

At this time, the extent to which natural enemies will control SLF is unknown. In Pennsylvania, natural enemies of other planthoppers do not appear to play a role in controlling SLF, and relatively few parasitoids are known to parasitize nymphs in the lanternfly family. In China and South Korea, however, native parasitic wasps have been shown to be important biocontrol agents for eggs and nymphs, but these species are not currently found in North America. In China, adults prefer feeding on tree-of-heaven, which contains cytotoxic alkaloids that makes them unpalatable to predators. The vivid red, black, and white coloration of nymphs and adults may serve as an indicator of their toxicity to potential predators. Adults will startle and scare predators by flashing their hindwings. 

Chemical Control

Research has shown that SLF nymphs and adults are susceptible to insecticides (Park et al. 2009; Shin et al. 2010); however, nearby SLF populations can repopulate treated areas (Kim et al. 2011). Insecticides that appear to be effective against SLF nymphs and adults and those that are currently registered in Utah are listed in Table 1. Not all products are labeled for all uses; therefore, be sure to consult the label for crop types and usage rates. Rotate among insecticide classes/modes of action (MoA) to reduce the development of chemical resistance. Use every precaution to protect surface water and groundwater from pesticide contamination. Choose the least toxic insecticide possible, and do not apply insecticides while pollinators are active. Many native insects utilize trees at the same time as SLF and could be affected by applications. Neonicotinoid insecticides (MoA:4A) have been associated with bee health decline. Additionally, pyrethroids  (MoA:3A) can affect beneficial insects and may cause increases of secondary pests such as mites and scales (Leach et al. 2020).

 

Table 1. Examples of insecticides that have
shown to be effective against SLF. Insecticides
are sorted by modes of action (MoA)
Examples of insecticides shown to be effective against SLFExamples of insecticides that have been shown to be effective against SLF 

References and Further Reading

Image Credits

1 PA Dept. of Agriculture, Bugwood.org
2 Emilie Swackhamer, Pennsylvania State University, Bugwood.org (left image); PA Dept. of Agriculture (right image)
Eric R. Day, Virginia Polytechnic Institute and State University, Bugwood.org
4,9 
Emilie Swackhamer, Pennsylvania State University, Bugwood. org
5,10 Lawrence Barringer, PA Dept. of Agriculture, Bugwood.org
6 Emilie Swackhamer, Pennsylvania State University, Bugwood.org (left image); Lawrence Barringer, PA Dept. of Agriculture, Bugwood.org (right image)
7 William M Ciesla, Forest Health Mgt International, Bugwood.org (left image); Joseph Berger, Bugwood.org (right image)
8 Erica Syers, Pennsylvania State University (both images)
11 PA Dept. of Agriculture, in https://extension.psu.edu/spottedlanternfly-management-for-homeowners 

Last Updated: 20 December 2020

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