spotted lanternfly

The spotted lanternfly (''Lycorma delicatula'') is a planthopper indigenous to parts of China. It has spread invasively to Japan, South Korea, and the United States. Its preferred host is tree of heaven (''Ailanthus altissima''), but it infests economically significant plants including soybean, grapes, stone fruits, and ''Malus'' spp. In its native habitat, ''L. delicatula'' populations are kept in check by parasitic wasps.

The spotted lanternfly's life cycle is often centered on its preferred host ''Ailanthus altissima'' but ''L. delicatula'' can associate with more than 173 plants. Early life stages (instars) of the spotted lanternfly are characterized by spotted black and white nymphs that develop a red pigmentation and wings as they mature. Early life instars display a large host range that narrows with maturation. Adult spotted lanternflies display a black head, grey wings, and red hind wings. Adults do not display any specialized feeding associations with herbaceous plants but have been known to cause extensive damage to crops and ornamental plants. The piercing wounds caused by their mouthparts and the honeydew waste they excrete have been found to be significantly detrimental to the health of host plants.

The species was accidentally introduced into South Korea in 2006 and Japan in 2009, and has since been considered a pest. In September 2014, ''L. delicatula'' was first recorded in the United States, and it is an invasive species in much of Northeastern United States. ''L. delicatula's'' egg masses have been found to be the primary vector of spread, with ''Ailanthus altissima'' populations seen as a risk factor for further infestation globally. Ongoing pest control efforts have sought to limit population growth, due to the threat ''L. delicatula'' poses to global agricultural industries.

Taxonomy and discovery

''Lycorma delicatula'' is a species in the genus '' Lycorma'', in the planthopper family Fulgoridae, subfamily Aphaeninae. Species within this genus are found in Asia. ''L. delicatula'' was originally described by Adam White in 1845 as ''Aphaena delicatula'', and the first scientific collections were made outside of Nankin, China. White described the species as similar to ''Aphaena variegata'', another planthopper species native to Asia, and referenced prior descriptions by George Tradescant Lay in his initial classification of the spotted lanternfly.

In 1863, the species was reclassified by Carl Stål as ''Lycorma delicatula delicatula'', with two additional subspecies described: ''Lycorma delicatula jole'' and ''Lycorma delicatula operosa''. Taxonomic classification places three other species ('' L. imperialis'', '' L. meliae'', and '' L. olivacea'') as closely related to the spotted lanternfly. The name ''Lycorma delicatula'' derives from ''lyc/lyco'', meaning "lamp" and ''delicatula'', meaning "luxurious". ''L. delicatula'' is also referred to as the spot clothing wax cicada ("chu-ki" or "banyi-la-chan" in Chinese) and the Chinese blistering cicada ("ggot-mae-mi" in Korean).

In 2019, the genome of ''L. delicatula'' was fully sequenced, with ''Aphaena amabilis'', and ''Pyrops candelaria'' both being classified as close relatives.

Description

Adult ''L. delicatula'' measure about long and wide. Adult lanternflies have a black head and gray-brown forewings adorned with black spots. White's original account identified ''L. delicatula'' as having a minimum of 20 black spots, with 6 spots located on the anterior margin of the forewings.

When resting, the crimson hind wings are partially visible through the semi-translucent forewings, giving the lanternfly a red cast. Neatly spaced black rectangular markings color the tips of the forewings in a pattern sometimes likened to brick and mortar. In flight, the spotted lanternfly displays red hind wings with black spots on the proximal third, a white wedge in the middle of the wing, and a solid black wing tip. The abdomen is yellowish with black and white bands on the top and bottom. ''L. delicatula'' displays orange, bulbous antennae covered in needle-like tips.
The spotted lanternfly is sexually dimorphic. Females have a set of red valvifers at the distal end of the abdomen, which males lack. When gravid (mated), the females' abdomens swell to the point where they have difficulty moving. Adult females, when measured from head to wing tip, have a body length of while males are a smaller size, between . Females also have longer legs as compared to those of their male counterparts.

The lanternfly is a planthopper, and uses its wings to assist these jumps rather than making sustained flights. The spotted lanternfly will perform a number of "successive collisions" upon jumping, employing both passive and active righting as it falls. This bouncing provides nymphs, and to a lesser extent adults, multiple opportunities to repeatedly attempt righting themselves following a jump. Additionally, the spotted lanternfly will also perform aerial reorientation and terrestrial righting as means to right itself, collectively giving the spotted lanternfly the ability to land on a variety of surfaces and spread rapidly through an environment.

Host associations

''Ailanthus altissima'' is a tree native to China and invasive to many other areas worldwide. It is considered to be the key host for ''L. delicatula'' and plays an important role in the lanternfly life cycle. This tree is the preferred host at all documented locations where the lanternfly and ''A. altissima'' co-occur. The spotted lanternfly has a host range of over 173 plant species worldwide, including grape vines, fruit trees, ornamental trees, and woody trees, including apple trees and several Rosaceae with stone fruits.

The spotted lanternfly has feeding behavior associated with 103 plant taxa, accounting for 33 families and 17 orders, with 56 of these occurring in the United States. This host range includes many agricultural crops most significantly soybean (''Glycine max'')

and common forest plants, as the nymphs have been known to associate with other plants beyond ''A. altissima''. The lanternfly has also been recorded causing serious damage on at least 12 ornamental plants such as ''Parthenocissus quinquefolia'', ''Phellodendron amurense'', and ''Toona sinensis''. In the United States, high populations are seen infesting common forest trees, such as maple, birch, and walnut; in Pennsylvania alone, ''L. delicatula'' has been found on more than 20 newly recorded host species of woody plants.

''L. delicatula'' feeds on woody and nonwoody plants, piercing the phloem tissue of foliage and stems with specialized mouthparts, and sucking the sap; it does not eat the fruit or the leaves ''per se''. The sugary waste fluid they produce can coat leaves and stems, which encourages mold growth and can impede photosynthesis.

''Lycorma delicatula'' feed on sap from the trunk or branches of their host plants; because they can appear in such large numbers on a single plant, they can directly cause substantial damage to, and effectively kill parts or the whole of the host.

''L. delicatula'' also indirectly affects the health and productivity of their hosts and nearby plants through the production of large amounts of honeydew, the lanternfly's sugary secretions of excess waste and sap, as well as by leaving feeding scars in the host plant's branches that continue to drip sap. The accumulation of this thick honeydew and tree sap on leaves below the host plant canopy can lower plants' photosynthetic potential and affect their health; this reduction is even more pronounced by the possible growth of molds over the sugary compound, which further limits light available to affected plants. The accumulation of sap and honeydew also attracts many species of ants, bees, and wasps; infestations of ''L. delicatula'' may thus be hinted at by unusual amounts of molds or stinging insects around specific plants.

Life cycle

Beginning in late April to early May, nymphs hatch from their egg cases. A nymph passes through several immature stages, all of which are wingless. In the first instar, it is black with white spots. Later instars have red patches in addition to the white spots. The final nymphal instar has red wing pads and a red upper body, before molting to the adult form, with a black head and grayish wings with black spots. Nymphs hop or crawl to search for plants on which to feed. Young nymphs (first through third instars) appear to have a wider host range early on, which narrows as they grow older. Though lanternflies have been recorded feeding on several herbaceous plants, this is most likely due to early-instar nymphs climbing or falling onto these plants; late-instar nymphs and adult lanternflies have no reliable association with herbaceous plants.

As early as July, adults can be seen, and they mate and lay eggs from late September through the onset of winter. During mating periods, spotted lanternflies will perform migratory flights. During these migrations, adult ''L. delicatula'' will perform a brief courtship and copulation which will last for up to 4 hours. In their native Indomalayan habitat, they lay their eggs preferably on tree of heaven (''A. altissima''), which has toxic metabolites, and is an introduced invasive tree in North America. This host choice is thought to have evolved as a mechanism of protection from natural enemies.

The spotted lanternfly has been found to be capable of completing its life cycle with hosts other than ''A. altissima,'' but generally fail to thrive unless ''A. altissima'' is present. Many hypotheses are given as to why ''L. delicatula'' may have preferences for feeding on certain plants. Two examples of possible factors being investigated are the contribution of the overall sugar composition in the plant and the presence of toxic chemicals. The lanternfly lays eggs upon any smooth-trunked tree, stone, or vertical smooth surface, including man-made items such as vehicles, yard furniture, farm equipment, or other items stored outside.

The egg masses contain 30–50 eggs covered in a yellowish-brown, waxy deposit, often referred to as an egg case. ''L. delicatula'' eggs undergo diapause during embryonic development, requiring two weeks of warm temperatures following winter before hatching is induced. Eggs overwintered for five months or longer demonstrate higher hatch rates and more synchronous hatching, suggesting that cold temperatures increase overall egg survival rates. The lanternfly's life expectancy is one year and the majority of adults die off by the end of December.Testing has been done to determine how overwintering affects the eggs of the species. The highest temperature that will still kill eggs was estimated by South Korean researchers to be between on the basis of mean daily temperatures during their winter of 2009–2010. This estimate contrasts with eggs having survived the much colder winter 2013–14 temperatures in Pennsylvania, United States. Another study done at Rutgers University suggested that is about the temperature at which no eggs are hatched, while still had limited hatching, depending upon how long they were chilled and where they were kept.

Distribution

Native range

The spotted lanternfly is originally native to parts of China, with some evidence of it being native to parts of India, Vietnam, and Taiwan. Fossil evidence indicates ''L. delicatula'' evolved between 55 and 51.6 myr, during the Ypresian Era. Phylogenomic analysis has shown that ''L. delicatula'' originally evolved in southwest China, eventually diverging into six phylogeographic lineages. One of these lineages then moved northward, following the Yangtze River during the late Pleistocene Era.

In the 1930s, ''L. delicatula'' was known to inhabit the Northern Provinces of Shanxi, Shandong and Hebei. Since then, it has expanded its range to include Anhui, Beijing, Guangdong, Henan, Jiangsu, Sichuan, Yunnan and Zhejiang. In traditional Chinese medicine, the spotted lanternfly is believed to be poisonous, and has been used since the 1100s for topical relief from swelling. ''L. delicatula'' has also been reported in Taiwan, Vietnam, and India, but ongoing research has yet to conclude if the species is native to these regions.

Accidental introduction

''Lycorma delicatula'' normally uses ''A. altissima'' for feeding and laying eggs, but if it is not present, the insect can lay its eggs on any stationary object, natural or man-made, and feeds on a wide variety of plants. Eggs can easily be moved from place to place without being noticed, giving them an easy way to spread to new areas. Its initial introduction to the United States is believed to have been through this pathway, hitchhiking on an object imported from Asia into Pennsylvania. Adults of ''L. delicatula'' jump around the area to find new host plants. As nymphs, they feed on whatever host plant the egg was laid on before moving to another in the area. ''L. delicatula'' is capable of surviving and completing its life cycle in environments without its preferred host, ''A. altissima'', albeit with greatly reduced fitness.

In South Korea

In 2006, the spotted lanternfly was introduced in Korea, and has been considered a pest since about 2007. It has since expanded its host range, attacking at least 65 plant species, uninhibited by natural predators. The distribution of ''L. delicatula'' has since been predicted using a modeling approach, which showed that this pest has the potential to occur in the majority of South Korea.

A possible correlation seems to exist between the widespread distribution of ''A. altissima'' and the overall damage on grapevines, as the tree is commonly found growing on the peripheries of Korean vineyards. ''L. delicatula'' has been documented to be a pest to grapevines, leading to a decline in the total number and overall quality of the harvested grapes. No quantitative data has been published supporting this correlation, but it has been widely hypothesized.

In Japan

In 2009, Japan reported their first confirmed presence of the spotted lanternfly in Komatsu city (Ishikawa Prefecture). In 2013, it was confirmed to have spread into the Fukui Prefecture. Researchers have estimated that the spotted lanternfly may have been entering the country sporadically since the 1930s, with it only establishing a population during the last two decades. Specimens found in Japan are genetically identical to populations in Beijing, Tianjin, Qingdao, and Shanghai, China.

In the United States

On 29 September 2014, the Pennsylvania Department of Agriculture (PDA) and the Pennsylvania Game Commission first confirmed the presence of the spotted lanternfly in Berks County, Pennsylvania, northwest of Philadelphia. Based on its host affinities, it presented a threat to the state's grape, fruit tree, and logging industries. The greatest risk of spread was seen in transportation of materials containing egg masses laid on smooth bark, stone, and other vertical surfaces.

The Pennsylvania Department of Agriculture banned the transport of items that could harbor the egg masses, including firewood, lawn mowers, outdoor chairs, trucks, and recreational vehicles from seven municipalities on 1 November 2014. Given the presence of old egg masses found, it has been estimated that the spotted lanternfly may have been in the United States since at least 2012, having survived the unusually cold 2013–14 winter. Since then, over 34 counties in Pennsylvania have declared quarantine.

Pennsylvania State University has estimated statewide costs of the spotted lanternfly to be $99.1 million in agricultural losses, and $236.3 million to the forestry industry, annually. Models of the spotted lanternfly's spread have projected an annual loss of $554.0 million, with an additional loss of 4,987 jobs, should it continue to spread to the entirety of Pennsylvania. A national working group led by the U.S. Department of Agriculture, consisting of Penn State Researchers and USDA scientists, was organized "to determine what is known about the lanternfly and what research is needed, including DNA analysis to pinpoint where the infestation originated."

Other states began seeing spotted lanternflies as soon as 2018, and by 2021, they were also confirmed to be established in at least parts of Connecticut, Maryland, Massachusetts, Delaware, New Jersey, New York, Ohio, Indiana, Virginia, and West Virginia, with several of these states issuing quarantine orders. In 2022, the species was confirmed to be present in North Carolina. A large potential range exists for the spotted lanternfly to become established if not prevented, covering almost all of the eastern part of the country, as well as critical wine- and hop-growing valleys of the Pacific coastal states.

Interceptions of dead spotted lanternfly specimens have been reported in Michigan, Kansas, Oregon and California, though no live sightings have been reported from these states This increases concerns for possible accidental introduction of the insect to yet more states where they can potentially become established.

In Canada

Canadian Food Inspection Agency has identified a risk of the Spotted Lanternfly entering the country and has previously intercepted adult lanternflies traveling to Ontario in shipping crates. The primary concern is the potential damage the lanternflies could cause to the wine, fruit, and vegetable industries. The Canadian government and agricultural industries are concerned about maintaining quarantine and have expressed hope that quarantine efforts in the United States are successful. Although most of Canada is an unsuitable habitat for ''L. delicatula'', southwestern Ontario and southerly parts of other provinces are modeled to have low suitability for inhabitation. ''L. delicatula'' has been theorized to be capable of maintaining a small population in the region although no specimens have yet been discovered.

In Europe

The European and Mediterranean Plant Protection Organization classifies ''L. delicatula'' as an A1 pest and anticipates it becoming invasive in Europe. CLIMEX modeling of potential habitats for ''L. delicatula'' has found that the United Kingdom, France, Belgium, Switzerland, Spain, and Italy may be capable of supporting small ''L. delicatula'' populations. Risk analysis of the spotted lanternfly to become established in Europe has been classified as a moderate to high risk, predominately due to the pervasiveness of ''A. altissima''.

In Australia

Modeling for the life cycle of the spotted lanternfly in Australia has found that development and survival may vary throughout the country, should the spotted lanternfly be introduced. Australia's southwest coastal regions are estimated to have a high viability for the spotted lanternfly but Australian Great Dividing Range and Tasmania were found to have the lowest suitability. Both the pervasiveness of ''A. altissima'' and the lack of consistent freezing seasons are considered risk factors in ''L. delicatula'' establishing populations in the country.

Possible pest control

Pest control measures and guidelines have been issued by the Pennsylvania Department of Agriculture and its PennState Extension. These guidelines include killing ''L. delicatula'' eggs between the months of October and May by scraping them off surfaces, "double bag them and throw them in the garbage." People can scrape the eggs directly into plastic bags containing alcohol and/or hand sanitizer to kill them. The PDA has recommended removal of spotted lanternfly hosts, the tree ''Ailanthus altissima'', saving only male trees to use as "trap" trees, since the spotted lanternfly requires a meal from this tree before laying eggs.

The remaining male "trap trees" should be wrapped with sticky bands starting in early spring to catch any nymphs. Wildlife experts have warned to cover the sticky bands on trees with chicken wire or another similar wire after many reports of other animals (e.g. birds) becoming trapped on them, resulting in injury and/or death.

the PDA recommended several different pesticides to treat infestations, including insecticidal soaps, neem oil, pyrethrins, and essential oils, as well as bifenthrin, carbaryl, dinotefuran as bark spray, imidacloprid, spinosad, tebuconazole, and zeta-cypermethrin. Infested trees can be treated with systemic pesticides from June to August. The PDA recommends tree injection and bark sprays, applied by professional applicators, and soil drench and foliar sprays, which can be applied by homeowners.

In Pennsylvania and Korea, use of brown sticky traps has been effective at capturing nymphs, though adults may be strong enough to escape the adhesive. The spotted lanternfly is known to avoid changes in tree texture and obstacles along the tree trunk, and inward facing traps have shown the greatest efficacy with minimized ecological impact. ''L. delicatula'' has been found to be attracted to certain kairomones released by their host plants, and adults and second- to fourth-instar nymphs are also attracted to spearmint oil. Such chemicals (like methyl salicylate) may be used to lure them into sticky traps to augment this pest control method.

Researchers using infrared thermography have found that the spotted lanternfly emits long-wavelength infrared (8–14 μm) light during active feeding and rapid hemolymph circulation, indicating a means of early detection. Trained dogs are capable of detecting winterized egg masses.

researchers are investigating another method of controlling lanternfly populations through reduction of ''Ailanthus altissima'' populations; the use of a fungal pathogen, ''Verticillium nonalfalfae'', has been found to effectively kill the invasive trees by causing vascular wilt. It is thought that lanternflies, which feed on this host plant by piercing and sucking the sap from its vasculature, may be able to "aid" in the ongoing removal of ''A. altissima'' by functioning as a vector for the ''V. nonalfalfae'' pathogen between different individuals of the insects' preferred host. Researchers have not yet found this to be an effective method, and more research is needed to confirm if this is possible in field settings with ''V. nonalfalfae'' or other pathogens.

Four species of fungal entomopathogens native to the United States have been identified to cause co-epizootics in the spotted lanternfly. ''Beauveria bassiana,'' ''Batkoa major'', '' Metarhizium pemphigi'' and ''Ophiocordyceps delicatula'' (in the family Entomophthoraceae) have been found to parasitize and kill the spotted lanternfly, with ''Beauveria bassiana'' having also shown an ability to kill spotted lanternflies in biopesticide trials.

A few natural predators have been identified in the lanternfly's native habitat in China, but are not yet used in biocontrol. ''Dryinus sinicus'', a dryinidae wasp, and '' Ooencyrtus kuvanae'', a chalcid wasp, have been found to parasitize spotted lanternfly eggs and nymphs. ''Ooencyrtus kuvanae'' was previously introduced into the United States in 1908 for population control of ''Lymantria dispar dispar'' and was first documented to parasitize spotted lanternfly egg masses in 2017. Another biocontrol predator being tested is the eupelmid wasp ''Anastatus orientalis'', due to its high rates of parasitism of eggs. This wasp is under investigation in South Korea and in the United States, where it is being evaluated under quarantine until researchers are certain it will not become an invasive species and attack other insects.

Potential benefits

Spotted lanternfly DNA has been confirmed in southeast Pennsylvania honey samples, presumably caused by honeybees consuming lanternfly honeydew. The honeydew secreted by lanternflies which had feasted on the tree of heaven not only led to changes in flavor deemed beneficial to the marketing of late-summer Pennsylvania honey, but was reported to have less ash content than aphid honeydew. This property makes lanternfly honey a better cold-weather food source for bee colonies and confers some resistance to parasitic mite infestations.

Photos

File:Spotted Lanternfly Berks County PA Late July 2018.jpg, Late-instar nymphs of spotted lanternfly on ''Vitis labrusca'' in Berks County, Pennsylvania, in late July 2018
File:Spotted lanternflies in BBG (42943).jpg, Adult spotted lanternflies in Brooklyn Botanic Garden
File:Spotted Lanternfly in Web.jpg, Adult spotted lanternfly caught and eaten by a spider in Delaware County, Pennsylvania
File:Spotted lanternfly (Lycorma delicatula).jpg, Spotted lanternfly late-instar nymph
File:Lanternfly nymph - 06.13.22.jpg, alt=, Spotted Lanternfly early-instar nymph on a grape leaf

References

External links

Hungry Pests Campaign – Spotted lanternfly
United States Department of Agriculture

Species Profile – Spotted lanternfly (''Lycorma delicatula'')
National Invasive Species Information Center, United States National Agricultural Library

PennState Extension spotted lantern information page
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{{Taxonbar, from=Q10571341

Agricultural pest insects
Aphaeninae
Endemic fauna of China
Hemiptera of Asia
Insect pests of temperate forests
Insects described in 1845
Taxa named by Adam White (zoologist)