Wednesday, September 28, 2022

All are Asked to Kill this Very Bad Bug

The deceptively attractive, Spotted Lanternfly (SLF) or Lycorma delicatula, is an invasive planthopper native to China, India, and Vietnam.

Adult Spotted lanternflies measure about 1-1.25 inches long, Photo Credit: As found on Google courtesy of Phys.org

In Asia, their populations are kept in check by parasitic wasps, however, no natural predators exist here.

In America, the SLF were first discovered in Berks County, Pennsylvania in 2014. Despite efforts to quarantine and check vehicular transports to and from the affected areas, they quickly spread and established themselves throughout the eastern states. This was apparently due to their penchant for riding on any flat surface, including the undercarriage of vehicles, shipments of nursery materials, clothes, backpacks, etc.

With no known predators in America, this bug is spreading fast. Photo Credit: As found on Bing from nysipm.cornell.edu

Negative effects of the SLF have been felt in Agricultural and forest industries, as well as by homeowners and business owners who have to contend with the hundreds that will descend onto sunny sidewalks and patios.

According to the National Park Service website, (www.nps.gov), newly laid splotchy egg masses can be found on or underneath any outdoor structures. Each contains about 30-50 brownish seed-like deposits in 4-7 columns, measuring roughly an inch long. They can “have a gray mud-like covering which can take on a dry cracked appearance over time.”

Often, they are laid near the tree canopy requiring a strong sprayer to dislodge them. When they fall to the ground, they must be stomped on completely, squished with rocks and/or deposited in containers with rubbing alcohol, sanitizer or dish soap to kill them and thus try and reduce future populations.

In late April and early May, young nymphs emerge as harmless, albeit strange looking, black and white polka dotted, small bugs. They grow bigger, turning bright red with white spots and black stripes. They progress through four nymph stages (also known as instars) from April to July.

Just before Fall and through December, they change again into winged adults. Their gray forewings have black spots of varying sizes. The wing tips have black spots outlined in gray. Hind wings have contrasting patches of red and black with a white band. The legs and head are black, and the abdomen is yellow with black bands.

The SLF, in its various phases, can be confused with eastern boxelder bugs and several species of moths. It has been found that the distinctive red color of the late instars and adults may have evolved to show predators that they are poisonous, causing regurgitation.

Spotted lanternflies’ life cycle. Photo Credit: Found on Bing from nysipm.cornell.edu

Although the adults can fly and often launch themselves from high poles, they generally prefer to hop/jump and glide exposing their hindwings. Additionally, the hindwings are exposed when they are frightened or treated with an insecticide. They’ve been found to jump as far as 10 feet and are said to be lightning-quick.

The SLF feed on a variety of host plants including fruit trees, ornamental trees, woody trees, vegetables, herbs, grains and vines.  They are known to feed on over 70 host plant species by sucking sap through piercing-sucking mouth parts.

They then excrete the juice, called honeydew, creating black sooty mold at the base of their hosts, or on cars and play equipment left underneath infected trees. Yellow jackets are attracted to the sugary honeydew.

Tree of Heaven (TOH), or Ailanthus Altissima, is the preferred host of the SLF. It is so named because it’s often found in cemeteries due to land disturbance and is considered an invasive species which is easily mistaken for staghorn sumac, a native that grows in similar soils and areas.

According to the PennState Extension website (https://extension.psu.edu/tree-of-heaven), “The tree was initially valued as a unique, fast-growing ornamental shade tree with the ability to grow on a wide range of site conditions, tolerating poor soils and air quality… By the early 1900s the tree began losing popularity due to its “weedy” nature, prolific root sprouting, and foul odor. Tree-of-heaven has spread and become a common invasive plant in urban, agricultural, and forested areas.”

PennState Extension further cautions, “This species is easily confused with some of our native trees that have compound leaves and numerous leaflets, such as staghorn sumac, black walnut, and hickory.” As these native trees may be valuable to our ecosystem, it’s best to consult with licensed foresters or Certified Tree Experts before embarking on tree removal to combat the SLF.

Tree of Heaven
Invasive Tree of Heaven – Preferred host for the Spotted lanternfly.
Photo Credit: As found on Bing courtesy of Cornell University

SLF eradication has mainly centered on killing the invasive Ailanthus or using them as bait trees to attract the SLF adults. Although Ailanthus is preferred, possibly required, to host the Spotted lanternfly for reproduction, feeding behavior varies depending on life stage.

The nymphs are easiest to trap and kill. DIY steps taken to kill the SLF have involved using industrial fly swatters, super soakers and spray guns filled with dish soap have been effective in knocking them out of trees where they can be vacuumed up with shop vacs.

Although desperate homeowners have resorted to using sticky tape around trunks, it is NOT recommended due to the high mortality of hapless birds and squirrels who meet a gruesome fate when stuck there.

Several institutions are studying alternative ways to kill the creatures. In 2019, the Adirondack Almanack reported in their paper, ‘A pair of native fungal pathogens drives decline of a new invasive herbivore,’ published in the Proceedings of the National Academy of Sciences, that two naturally occurring but unrelated fungi, Batkoa major and Beauveria bassiana, have been parasitizing SLF populations in Berks County, Pennsylvania.

Researchers there confirmed that SLF found dead on the ground were killed by both B. bassiana (49%) and B. major (51%). Almost all (97%) of those found dead on trees were killed by B. major. The fungi appear to have only minimal impact on native insect species.

Eric Clifton, a Cornell University postdoctoral researcher and co-author of the paper, described these findings as “a great example of how a major new invasive herbivore can be suppressed by native pathogens.” adding that “Nobody stepped in to do this; it all happened naturally.”

The paper further hypothesized that native insects may have built up a resistance to the fungi over time, but SLF, because they may have never encountered these native fungi before, are unusually vulnerable.

Still, according to Clifton it can’t be guaranteed that the fungi will stop the spread of lanternflies. He added, “It’s not going to kill all of them. But there is a chance that it will at least help to stabilize populations into the future.”

We can only hope his findings prove true, but in the meantime, it’s best to prepare for the inevitable insect onslaught. It has a strong preference for economically important plants and the feeding damage significantly stresses the plants which can lead to decreased health and potentially death.

With no significant preference for Tree of Heaven, early instar nymphs have a broader menu. Infestations become evident when hundreds of SLF crawl through the grass and swarm up smooth-barked trees, or conversely, land on decks, patios, parking lots and sidewalks.

According to a Kutztown University SLF Host Study, late season adults tend to prefer trees other than TOH, like silver maple, willow, etc, possibly due to sap flow. The proximity of TOH to other preferred hosts was found to have no significant effect on how many SLF were found per tree. There is currently research underway to determine if SLF requires feeding on TOH to complete its lifecycle.

The Spotted Lanternfly has the potential to greatly impact agricultural crops and hardwood trees and is decimating fruit and grape growers in Pennsylvania and Upstate New York. SLF feeds on the plant sap of many different plants including grapevines, maples, black walnut, and other important plants in New Jersey.

Why Should You Care?

SLF is a serious invasive pest with a healthy appetite for our plants and it can be a significant nuisance, affecting the quality of life and enjoyment of the outdoors. The spotted lanternfly uses its piercing-sucking mouthpart to feed on sap from over 70 different plant species.

Adult Spotted lanternflies swarm toward a tree to feed on sap.
Photo Credit: As found on Bing courtesy of Cornell University

It has a strong preference for economically important crops and the feeding damage significantly stresses the plants which can lead to decreased health and potentially death. Locally, adult SLF were seen last year at vineyards and farms in every town and as high as against the glass enclosing the station atop Hardwick’s Catfish Firetower.

What Can You Do?

  • See It, Stomp (Squish) It!
  • Check your vehicle for insect hitchhikers
  • Invest in extra-strength dish soap
  • Invest in large fly swatters, super soakers, spray guns.
  • Learn to identify SLF egg masses, look for them in your wheel wells and among your trees and outdoor structures,
  • Starting in Spring and again in Fall, scrape them off with spackle tools or credit cards into containers or bags filled with dish soap, which can be tightly sealed.
  • Properly identify and cut down any Tree of Heaven (Ailanthus) species on your property.
  • Professional advice should be sought from Certified Tree Experts or your local Cooperative Extension Office about how to remove an Ailanthus, due to the presence of multiple sucker roots.
  • Learn which tree species are on the SLF menu and don’t replace cut TOH with those trees.
  • To report a sighting, email SLF-plantindustry@ag.nj.gov.


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