The spotted lanternfly (Lycorma delicatula) is the new kid on the block and current poster child for runaway invasive pest insects in the United States. This bug, a member of the planthoppers (Auchenorrhyncha), hails from China and its surrounding countries. One of the reasons for its off the charts threat level is its polyphagous diet. The insect feeds on the phloem of plants in a broad range of taxonomic groups (Urban and Leach 2023). Many of those groups contain economically important plants, including but not limited to hops, grapes, apples, stone fruit, almonds, pine, and hardwoods like walnut (USDA 2023). The tree of heaven (Ailanthus altissima) is its preferred host. The spotted lanternfly was first detected in Pennsylvania in 2014 and it has since spread across a large portion of the eastern U.S. (New York State Integrated Pest Management Program 2023). The range is rapidly expanding and is projected to reach a majority of the country. Many quarantine zones have been established to help slow the spread (Urban 2020). Despite these efforts, the bug will almost certainly breach these boundaries and continue to grow in numbers. Although it does best with its preferred host, mentioned above, the lanternfly is capable of reproducing without access to this resource (Uyi et al. 2020). However, development time is slower and fewer egg masses are laid before the northeastern winter kills the remaining adults. But in states with warmer climates, it could potentially survive the winter and create more offspring (Uyi et al. 2020, Xin et al. 2020). This adaptability makes it an even more threatening economical and ecological pest.
The tree of heaven – a lanternfly’s favorite food (Credit: Pixbay)
The spotted lanternfly itself is quite stunning. In adults, the forewings are leathery in texture and a pinkish grey with contrasting black spots. This color becomes criss-crossed with a mosaic of yellow veins on the distal third of the wings. Underwings are striking red and black with a white bar on each one. The first three instars of the immature stage are black with white spots and become an intense red with black and white spots by the fourth and final instar. Being beautiful does not give these insects a pass, though. Large congregations, sometimes up to 1,000 per tree (Urban 2020), in urban and suburban areas excrete large quantities of honeydew that results in sticky buildup beneath the plants on which they feed. This sugary coating encourages the growth of sooty mold that severely impacts the health of affected plants (Urban and Leach 2023). This is becoming particularly problematic in vineyards (Urban, 2020). The mouthparts of lanternflies also leave seeping wounds in plants, causing physiological stress and leaving an entry point for pathogens (Uyi et al. 2020). Controlling the dispersal of spotted lanternflies can be very difficult because of how flexible the insects are with where they lay their eggs.
Sooty mold growth caused by honeydew (Credit: Scott Nelson)
Management strategies are evolving as more is learned about the lanternfly’s life history and ecology as it pertains to the United States. Great care must be taken when transporting goods and equipment from areas where infestations occur. Lanternflies will lay their eggs on trees, cut wood, concrete, in the wheel wells of vehicles, and on any other natural or artificial surface that is suitable (Urban and Leach 2023). Local and federal government departments have information readily available about the pestilential planthoppers and how citizens can combat them. The primary directives are to smash adults and nymphs on site, check belongings before traveling or transporting anything in and out of buildings, destroy any egg masses found, and report sightings to help track the spread (USDA 2023).
The life cycle of a spotted lanternfly (Credit: USDA)
The standard method of agricultural and environmental industry control remains the application of chemical insecticides, particularly the neonicotinoid dinotefuran and a variety of pyrethroids. The downside to these treatment strategies is the negative effect they can have on non-target species when applied to large areas (Urban and Leach 2023). Emerging control methods that are less environmentally harsh consist of exclusion netting, targeted insecticide application, and bio pesticides such as Beauveria bassiana, a soil dwelling fungus. Other entomopathogenic fungi are currently being explored as options as well (Urban and Leach 2023). Xin et al. (2021) surveyed parasitoids of the spotted lanternfly that occur in its native range, but more research is needed to determine whether they are practical as biological control agents.
A spotted lanternfly adult with its brilliant red hind wings displayed (Credit: Chesapeake Bay Program)
As the spotted lanternfly invasion problem continues to evolve, many challenges are arising. The use of pesticides, as mentioned, can impact unintended targets. There is also potential for the bugs to develop resistance to the chemical weapons we throw at them. Less environmentally harmful substances including neem and essential oils have shown only mild efficacy at a local level. Sticky traps encircling tree trunks sometimes kill birds and small mammals as bycatch and do not really have a significant impact on heavy populations of lanternflies anyway (Urban and Leach 2023). There is no perfect solution and management strategies will have to change along with the pest. Only time will tell what level of havoc this beautiful destroyer will wreak upon our economy, agricultural industries, and environment.
Photo Links:
1. https://jenikirbyhistory.getarchive.net/media/ailanthus-altissima-tree-of-heaven-ailanthus-nature-landscapes-a52bd0
References:
1. Urban, Julie M., and Heather Leach. “Biology and management of the spotted lanternfly, Lycorma delicatula (Hemiptera: Fulgoridae), in the united states.” Annual Review of Entomology 68 (2023): 151-167.
2. “Spotted Lanternfly.” USDA APHIS | Spotted Lanternfly, USDA, 2023, http://www.aphis.usda.gov/aphis/resources/pests-diseases/hungry-pests/the-threat/spotted-lanternfly/spotted-lanternfly.
3. “Spotted Lanternfly Reported Distribution in the Eastern U.S.” Spotted Lanternfly Reported Distribution Map, Cornell University College of Agriculture and Life Sciences, Aug. 2022, https://cals.cornell.edu/new-york-state-integrated-pest-management/outreach-education/whats-bugging-you/spotted-lanternfly/spotted-lanternfly-reported-distribution-map. Accessed 8 Oct. 2023.
4. Urban, Julie M. “Perspective: shedding light on spotted lanternfly impacts in the USA.” Pest management science 76.1 (2020): 10-17.
5. Uyi, Osariyekemwen, et al. “Spotted lanternfly (Hemiptera: Fulgoridae) can complete development and reproduce without access to the preferred host, Ailanthus altissima.” Environmental Entomology 49.5 (2020): 1185-1190.
6. Xin, Bei, et al. “Exploratory survey of spotted lanternfly (Hemiptera: Fulgoridae) and its natural enemies in China.” Environmental Entomology 50.1 (2021): 36-45.