Spotted lanternfly: The latest invasive species spreading through the eastern U.S.

A man is holding an adult spotted lanternfly to show its wings
Adult Spotted Lanternfly. Photo: M Raupp, UMD

¿Hablas español? Aquí esta una traducción: Mosca linterna con manchas: la especie invasora más reciente que se está extendiendo por el este de los Estados Unidos.

Spotted lanternfly (SLF), Lycorma delicatula (Hemiptera: Fulgoridae), is an invasive planthopper moving its way through the eastern U.S. SLF was first detected in the U.S. in 2014 in southeastern Pennsylvania. It is native to parts of Asia and believed to arrive as egg masses laid on landscaping stones shipped to PA. Despite quarantines and eradication efforts, SLF infestations have been confirmed in 12 states and detected in several others.

A map shows that spotted lanternfly is confirmed in 12 states in the northeast USA
Since spotted lanternfly was first detected in Pennsylvania in 2014, confirmed infestations are in 12 states as indicated by this map (as of June 30, 2022). Image: https://nysipm.cornell.edu/environment/invasive-species-exotic-pests/spotted-lanternfly/spotted-lanternfly-range-us/

As we look at the SLF distribution map, we can see that counties with infestations are hundreds of miles away from any other infestation. This is related to the fact that SLF are excellent hitchhikers, taking advantage of human-assisted transportation. Many infestations occur along major interstates and train lines. In addition, the nymphs are active walkers and adults are able to hop and fly to new host plants and locations. Researchers at Penn State found that some SLF nymphs travel as much as 213 feet, and adult flights ranged from 30 to 150 feet in their search to find suitable hosts.

In response to SLF’s impressive ability to disperse, states have implemented regulatory quarantines and permitting programs implemented through State Departments of Agriculture, which requests actions be taken by businesses and the public who travel in and out of SLF-infested areas.

What do we know about the life cycle of SLF?

The life cycle of SLF consists of one generation per year, with eggs (the overwintering stage) laid in the fall (September – November). Egg masses are laid on smooth surfaces such as tree branches, landscape stones, rocks, wood from decks or fencing, outdoor furniture and equipment, etc. Egg masses are covered with a mud-like substance likely for protection. The protective covering is gray when freshly laid and becomes brownish with age. The eggs hatch in the spring between 240 (usually early to mid-May) and 1100 (late June to early July) degree days (DDs).

Spotted lanternfly egg mass ona tree trunk
Freshly laid egg masses of spotted lanternfly are gray in color and camouflage well on tree branches and other structures. Photo: M.J. Raupp, UMD

There are 4 nymphal instars (immature stages). Newly hatched nymphs are small (~1/8”) and at each molt they somewhat double in size. The first three nymphal instars are black with white spots and the last nymphal instar is red with white spots and black stripes.

early instar spotted lanternflies
Early instar spotted lanternfly nymphs are often found on new growth of plants. Photo: PA Dept. of Agriculture
late instar spotted lanternfly nymph
Late instar (4th) nymphs are about ½” long, bright red with white spots and black stripes. Photo: D. Ludwick, Penn State Extension
Spotted lanternfly adult
The adult spotted lanternfly has beautiful coloration and is ~ 1 inch in length. Photo: M.J. Raupp, UMD

In PA, adults begin to emerge in July (50% adult emergence at ~ 1,100 DDs) and they remain active (feeding, excreting honeydew, mating, and laying eggs) until the first hard freeze, which kills them. Adults of this planthopper are beautiful and relatively large (~1”). Adults have black bodies and legs; their front wings are gray with black spots and the ends are black with gray veins. Their hindwings are red, black and white. When the adult spreads its wings, the bright red color is quite impressive. Nymphs and adults are robust jumpers and adults can also fly.

Why is SLF problematic?

SLF is a voracious feeder on over 70 different plant species, which include numerous economically-important plants such as grapevines, some herbaceous ornamental plants, fruit trees, numerous ornamental trees, and tree of heaven. It uses its piercing sucking mouthparts to remove phloem sap from its host plants. Hundreds to thousands of SLF individuals can sometimes be found on a single tree. Surprisingly, even at these high numbers, death of hosts is only known to occur on grapes and a few sapling trees, although branch dieback on trees has occurred. Further research is needed to determine the longer-term impact of the stress of so many SLF feeding on trees has on secondary problems.

In addition to damage to hosts from feeding, SLF is also considered a nuisance pest. SLF excretes large quantities of honeydew which drops down onto leaves, branches, tree bark, driveways, cars, and anything else that might be underneath an infested host. The honeydew also has its associated black sooty mold, which makes it more unsightly. On sunny days the honeydew can be seen “raining” down from SLF infested trees.

Abundant honeydew-/sooty mold-covered foliage may reduce photosynthesis and further stress trees. In addition, many bees, wasps, and other insects that feed on sweets are attracted to the sugar rich honeydew. Because densities of SLF are so high, the honeydew/sooty mold can be quite significant and impactful to homeowners and growers.

An impressive breadth of hosts

An interesting aspect of SLF’s ecology is that it changes the plants it feeds on as nymphs and adults develop over the season.

table showing host plants preferred by spotted lanternfly nymphs and adults
This table is a (non-extensive) representation of common host plants that spotted lanternfly feed on during the season. The table allows knowing when to start monitoring for activity of nymphs and adults, and what host plants they are likely to be on. It is recommended to always monitor for SLF infestations, since densities change over time both within the season and between years even on the same host plant. Tree of heaven, Ailanthus altissima, is an invasive tree and a highly preferred host. Information in this table is based on observations in Eastern Pennsylvania and may vary based on local conditions. Image: https://extension.psu.edu/spotted-lanternfly-management-guide.

How can SLF be managed?

Managing SLF is challenging, as is the case for many emerging, invasive species. It is unlikely you can stop it from coming onto your landscape or farm, and unlikely you can get rid of all of them. Given this, the goal is to reduce SLF populations to acceptable levels. Using an Integrated Pest Management (IPM) approach will result in the greatest success.

At this time, natural enemies are not reducing SLF populations. However, many generalist predators (spiders, assassin bugs, birds, etc.) are feeding on SLF, a parasitoid brought into this country years ago for spongy (formerly gypsy) moth control has been found attacking SLF, and two fungal pathogens were also identified, one of which (Beauveria bassiana) is commercially available. Further research is underway to identify measures to enhance the impact of these biological controls for SLF.

Cultural controls can be implemented. This includes destroying the overwintering egg masses, putting traps (circle or sticky traps) on trees to catch the nymphs and adults as they move up trees, and removing tree of heaven. Numerous studies have examined the efficacy of contact and systemic insecticides against SLF (see websites below).

We need you!

Please assist in tracking SLF to help slow the spread of SLF and improve its management. If you find SLF, please report it to your State Department of Agriculture or University Extension Service. In Maryland, report SLF at the MDA website (click on “Report Spotted lanternfly here”).

For more information

By Dr. Paula Shrewsbury, Professor and Extension Specialist in Ornamental and Turf IPM in the Department of Entomology at the University of Maryland

January Tips and Tasks

Snow covered shrub

  • Heavy snow and ice loads can damage shrubs. Using an upward motion, gently sweep snow loads off of shrubs to prevent breakage. But oftentimes bent or weighed down branches will spring back after the snow/ice melts.
  • Problem tree branches (hanging very low or storm damaged), may be removed as needed. It is not necessary to wait until spring for this type of pruning.
  • Cut back or stop fertilizing houseplants unless they are grown under supplemental lighting.

Houseplant

  • Avoid the temptation to start seeds too early. Check seed packets for detailed information on starting various types of flowers. Do not depend on window sill light to grow these seedlings. Refer to our instructions on starting seeds indoors.
  • Don’t store firewood inside your home. Only bring in enough to burn at one time. Bark and other wood boring beetles may emerge inside the home.
  • Be on the lookout for spotted lanternfly egg masses on the trunks of trees.

Spotted lanternfly egg mass
Spotted lanternfly egg mass
Photo: Emelie Swackhamer, Penn State University, Bugwood.org

Spotted Lanternfly Moves Into New Areas This Year

spotted lanternflies
Adult and 4th Instar Juvenile Spotted Lanternflies. Photo: Richard Gardner, Bugwood.org

Spotted Lanternfly (Lycorma delicatula) arrived in Maryland last year. These invasive insects are being controlled now in 15 sites in Cecil County and several in Harford County. The Maryland Department of Agriculture has expanded its survey sites along the Pennsylvania and Delaware borders to monitor for this pest. They also are surveying in Washington County since Route 81 goes through there. A Spotted Lanternfly infestation was found along Route 81 in Winchester, Virginia.

The map below shows (in blue) where state quarantines for Spotted Lanternfly are in effect in Pennsylvania, New Jersey, Delaware, and Virginia. Permits are required for any commercial or university vehicles doing business in the quarantine zone or passing through quarantine areas. Here is a link to the Pennsylvania permit page. Maryland has reciprocity with Pennsylvania for permits.

map showing spotted lanternfly distribution

This is a potentially very devastating pest that has over 70 host plants including vegetables, garden plants, many trees, and especially invasive Tree of Heaven (Ailanthus altissima) which it may need to feed on to complete its life cycle. Lanternfly adults are very active now and are in the process of laying eggs. Please be vigilant and report any sightings to the Maryland Department of Agriculture at Dontbug.MD@Maryland.gov.

adult spotted lanternflies and an egg mass
Adult Spotted Lanternflies and an Egg Mass. Photo: Richard Gardner, Bugwood.org

For the latest information, check out Penn State Extension’s website on Spotted Lanternfly. They are the leader in research on this pest and have excellent information, photos, and videos.

By Mary Kay Malinoski, Extension Specialist, University of Maryland Extension, Home & Garden Information Center

Yard and Garden Tips and Tasks for July

Spotted Lanternfly

Spotted lanternfly adults may be found feeding on many hosts, especially tree of heaven (Ailanthus altissma). Report any finds to the Maryland Department of Agriculture immediately, collect a sample or take digital photos of what you have found.

 

BagwormBagworm caterpillars are now very active. Look for little bags crawling around on evergreen trees and shrubs and be prepared to spray infested trees with the microbial insecticide, Bt by mid-July. Mature bagworms are not well controlled with Bt They are best collected by hand and destroyed or sprayed with insecticides containing spinosad.

 

Proper lawn mowing is critical to help it survive the summer. “Mow ‘em high and let ‘em lie” should be your mowing strategy. Cut your cool-season turf (fescues and bluegrass) to a height of 3-4 inches and leave the clippings on the lawn where they will naturally decompose.

 

BroccoliSow seed for fall transplants of broccoli, kale, turnip, and cauliflower in flats or containers by the 3rd to 4th week in July. Late crops of squash, beans, and cucumbers can be direct sown into your garden through the end of July.

 

More Tips and Tasks for July

Spotted Lanternfly Update: Be on the Lookout for Egg Masses

spotted lanternfly adult and eggs
Adult Spotted Lanternfly and egg masses. Photo: Kenneth R. Law, USDA APHIS PPQ, Bugwood.org

Spotted Lanternfly (Lycorma delicatula) is a new invasive pest in the mid-Atlantic region. The first Spotted Lanternfly in Maryland was confirmed in Cecil County in October 2018. (See the Maryland Department of Agriculture press release.)

honeydew and sooty mold
Honeydew and sooty mold from Spotted Lanternfly feeding. Photo: Kenneth R. Law, USDA APHIS PPQ, Bugwood.org

This insect is known to feed on 70 species of plants including forest and agricultural crops such as grapes, hops, apples, peaches, figs, oaks, maples, black walnuts, and tree of heaven. Spotted Lanternflies feed on plant sap and secrete a sticky substance called honeydew. Black sooty mold grows on the honeydew and blocks sunlight from reaching leaves, impairing photosynthesis. Plants may become weakened and more susceptible to secondary invaders such as ambrosia beetles. The long-term effect on the health of trees and vines is unknown at this time. Continue reading

Spotted Lanternfly: A New Invasive Pest That is Too Close for Comfort

spotted lanternfly adult
Spotted Lanterfly Adult. Photo: Pennsylvania Department of Agriculture, Bugwood.org

Spotted Lanternfly (Lycorma delicatula) is an insect native to China that was first detected in Southeastern Pennsylvania in September 2014.  It has spread fairly rapidly since then. There were recent finds in Delaware and New York. Both were dead individual adults.

spotted lanternfly quarantin map of pennsylvania november 2017
A quarantine is in place in several counties of Southeastern Pennsylvania to restrict the spread of Spotted Lanternfly. Source: Pennsylvania Department of Agriculture

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