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Bug of the Week is written by "The Bug Guy," Michael J. Raupp, Professor of Entomology at the University of Maryland.

Seeing spots: Spotted Lanternfly, Lycorma delicatula


Spectacularly beautiful but nonetheless harmful, spotted lanternflies provide yet another challenge in the never ending battle with invasive species.


A few weeks ago on a dreary late autumn weekend, Bug of the Week found itself at a truck stop along I-78 near New Smithville, PA. Like many truck stops, this one sported a ramshackle parking area rife with abandoned pallets, discarded oil cans, and disturbed soil. At the margin of the parking zone, a curious mix of native and non-native plants engulfed mounds of earth. Amongst the native sumacs and volunteer sycamores, tree-of-heaven made its presence known as a co-dominant species. On the smooth boles and branches of Ailanthus altissima, legions of spotted laternfly merrily sucked sap. In what has become a never ending stream of invasive species arriving in the US, Berks County, PA, witnessed the arrival of this new invasive insect pest in 2014. This area was made famous two decades ago with the arrival of an invasive species in neighboring Lehigh County, which registered the discovery of the infamous brown marmorated stink bug, a pest visited in several episodes of Bug of the Week. The spotted lanternfly is a relative of other laternflies we’ve met in previous episodes of Bug of the Week (Rain on a sunny day: Lanternflies, Fulgoridae, January 27, 2014). How it arrived in the US is not clear, but like many recent invaders this one appears to be a good stowaway.


On a rainy November day, spotted lanternflies lining the trunk of a tree-of-heaven suck sap and try to evade the inquiring lens of a bug geek’s camera.

The spotted lanternfly is not a fly but rather a planthopper, a true bug that injures plants with its piercing, sucking feeding method. All four nymphal stages and adults feed. The female lanternfly deposits eggs in rather nondescript batches of 30–50 cloaked with a waxy mud-like cover roughly one inch long that turns brown or gray with age. Beneath the cover, the eggs are seed-like and deposited in 4-7 parallel rows per mass. These egg masses are often laid on tree trunks but have also been discovered on substrates such as stones, vehicles, and lawn furniture. It is easy to see how this bug might have arrived undetected with a shipment of goods from a foreign land. China is the aboriginal home of the spotted lanternfly and it was detected in Korea in 2006, where it has become an important pest of many fruit bearing woody plants including grapes, apples, cherries, peaches, and more than 70 other ornamental species such as evodia, lilac, maple, and dogwood.

It’s easy to see how the non-descript egg masses of the lanternfly like this one on the bole of a tree sneak past human detection and move about the world.

In Pennsylvania, eggs hatch in April and May and the tiny nymphs insert their sucking beaks into leaves and stems and feed on the nutrient rich phloem tissue. Nymphs feed and shed their skin several times during the course of development over the summer. By late summer they complete development and molt to the adult stage. Males are slightly smaller than females, which average about an inch in length. Feeding by nymphs and adults robs the plant of valuable nutrients, and as a byproduct of their feeding large quantities of sugar-rich honeydew are produced. As we saw with some aphids, froghoppers, and sharpshooters, the waste product honeydew serves as a substrate for the growth of sooty mold, a non-pathogenic fungus that stains the plant black, impairs photosynthesis, and disfigures fruit and leaves.  After mating, females deposit eggs on a variety of surfaces until the cold winds of late autumn bring an end to the growing season.   

What has been done to stop the spread of this pest? To date more than 1.5 million spotted lanternflies have been killed by volunteers in Berks and surrounding counties. At present, a quarantine to stop its spread to new areas and slow its spread within the quarantined area has been placed around municipalities in thirteen Southeastern counties including the following (excerpted from Spotted Lanternfly, Pennsylvania Department of Agriculture):

Berks County - Albany, Alsace, Amity, Centre, Colebrookdale, Cumru, District, Douglass, Earl, Exeter, Greenwich, Hereford, Longswamp, Lower Alsace, Maiden Creek, Maxatawny, Oley, Ontelaunee, Perry, Pike, Richmond, Robeson, Rockland, Ruscombmanor, Union, and Washington townships; Bally, Bechtelsville, Birdsboro, Boyertown, Centerport, Fleetwood, Kutztown, Lyons, Mt. Penn, St. Lawrence, and Topton boroughs; Reading city.

Bucks County - Bedminster, Haycock, Hilltown, Milford, New Britain, Plumstead, and Richland townships; Chalfont, Dublin, New Britain, Quakertown, Richlandtown, Silverdale, and Trumbauersville boroughs.

Chester County - East Coventry, East Pikeland, East Vincent, North Coventry, South Coventry, Warwick, and West Vincent townships; Phoenixville and Spring City boroughs.

Lehigh County - Heidelberg, Lower Macungie, Lower Milford, Lowhill, North Whitehall, Salisbury, South Whitehall, Upper Macungie, Upper Milford, Upper Saucon, Weisenberg, and Whitehall townships; Alburtis, Catasauqua, Coopersburg, Coplay, Emmaus, and Macungie boroughs; Allentown and Bethlehem cities.

Montgomery County - Douglass, Franconia, Hatfield, Limerick, Lower Frederick, Lower Pottsgrove, Lower Providence, Lower Salford, Marlborough, New Hanover, Salford, Skippack, Towamencin, Upper Frederick Upper Hanover, Upper Pottsgrove, Upper Providence, Upper Salford, and West Pottsgrove townships; Collegeville, East Greenville, Green Lane, Hatfield, Lansdale, Pennsburg, Pottstown, Red Hill, Royersford, Schwenksville, Souderton, and Trappe boroughs.

Northampton County - Allen, Bethlehem, East Allen, Hanover, Lower Nazareth, Moore, and Upper Nazareth townships; Northampton and Nazareth boroughs; Bethlehem city.

Other PA counties also under quarantine as of November 4, 2017, include Monroe, Carbon, Schuylkill, Lebanon, Lancaster, Delaware, and Philadelphia counties.

This quarantine restricts the movement of “Any living stage of the Spotted Lanternfly, Lycorma delicatula. This includes egg masses, nymphs, and adults. Brush, debris, bark, or yard waste; landscaping, remodeling or construction waste; logs, stumps, or any tree parts; firewood of any species; grapevines for decorative purposes or as nursery stock; nursery stock; crated materials; outdoor household articles including recreational vehicles, lawn tractors and mowers, mower decks, grills, grill and furniture covers, tarps, mobile homes, tile, stone, deck boards, mobile fire pits, any associated equipment and trucks or vehicles not stored indoors.” Delimiting surveys were conducted to determine the spread of the bug and attempts are underway to destroy the pest where it is found. Pennsylvania received nearly $1.5 million of Federal aid to conduct research, implement control, and develop outreach programs. This was shared among several universities and government agencies.

What can homeowners do if they suspect they have this pest? The Pennsylvania Department of Agriculture has established a remarkable web site (link provided below) to assist citizens with identification of this new pest, learn how to destroy egg masses, and to report sightings. In an ever-changing world where a global economy has resulted in a global biota, let’s hope that the genie in Southeastern Pennsylvania doesn’t escape from the bottle before a way to manage the pest is found.


Bug of the Week thanks Sven-Erik Spichiger for providing the inspiration for this episode with his stellar presentation on this beast at the 86th Annual Meeting of the Eastern Branch of the Entomological Society of America. To learn more about the spotted lanternfly, please visit the following link: