Dan Donahue, CCE-ENYCHP, Hudson Valley, New York

The Spotted Lanternfly (SLF), Lycorma delicatula, is an invasive pest species first discovered in Northeastern Pennsylvania in 2014.

While the state of Pennsylvania and the USDA reacted quickly to establish a quarantine to prevent its spread, the insect is an accomplished traveler, managing to escape the region by hitchhiking on cars and trucks.  Eradication efforts were attempted, but ultimately not successful.  Active colonies (infestations) of SLF has been found in the Hudson Valley (see map below).

SLF is an insect with sucking mouthparts who feeds by inserting those mouthparts into the trunk and branches of trees, looking to tap into the plant’s vascular system (specifically the phloem for our botanist readers out there!).  The sap in the phloem is rich in nutrients and serves as the food source for our nemesis. On the bright side, those sucking mouthparts are akin to a “straw” and the very large adult cannot bite humans and animals, or sting with its abdomen like a bee or wasp.  SLF isn’t a direct feeder on fruit tissue so it’s feeding won’t cause direct physical injury to fruit, say like the half-moon shaped oviposition (egg laying) scar that can be easily found on apples at harvest in abandoned orchards. However, the potential problem for orchardists and vineyardists is the cometic damage to the fruit caused by microorganisms that thrive on the nutrient-rich “honeydew” excreted in volume while the insect feeds.  The honeydew accumulates on the fruits and the microbes that capitalize on the opportunity will produce a “sooty” substance that effectively discolors the fruit, preventing it from being sold.

Photo credit: NYS Integrated Pest Management Program Staff

This “cheeky” character landed on the hood of a tractor operating in an Orange County, NY, orchard this summer. Rumor has it that words were exchanged, but we cannot find any independent confirmation of this. Photo Credit: A grower (anonymous).

Known distribution of Spotted Lanternfly in and around the Hudson Valley of New York State as of September 21, 2022.  Blue shading shows the counties with active infestations (Ulster, Orange, Rockland and Westchester in the Hudson Valley).  Purple dots show the counties where individual SLF has been found, but no active infestations. Map provided by the NYS Integrated Pest Management Program.

SLF attacking a grape vine.  The large number of individuals is striking and note that they are feeding on the vine itself, not the fruit.  The nutrient-rich “honeydew” excrement produced is what coats the fruit underneath encouraging the development of microbes that ruin the fruit for sale.

 

A real challenge for commercial orchardists and vineyardists in the Hudson Valley and elsewhere will be how to manage this new pest so that populations remain below the level where they cause economic losses.  To this end, research is underway in the Hudson Valley to better understand the biology of this invasive species.  Being new to our region, agriculturalists are essentially at square one in understanding how well SLF will survive in our region, how significant the threat, and what steps commercial producers can take to reduce populations below the level of economic significance.

To that end, researchers at the Cornell Hudson Valley Laboratory in Highland, NY, has learned how to successful maintain a research colony of SLF in a confined laboratory setting.  Roberto Regalado, field technician, working with Ken Wise, both affiliated with the Cornell Cooperative Extension NYS Integrated Pest Management Program are busy convincing their captured SLF to feed and reproduce in their artificial ecosystem as if still in the wild.  No easy task as the insects will respond to environment stimuli such as temperature, light, humidity, and the quality of the food source, and sometimes not in a good way.  The natural ecosystem is complicated and it’s a real challenge to duplicate it well enough to convince the caged SLF to go about their lives in a natural manner.

The interior of the Cornell Hudson Valley Laboratory SLF colony showing the potted “Tree of Heaven” which are an invasive species in of itself and the preferred food source from the insect’s original home in Asia.   Tree of Heaven (Ailanthus altissima) is now widely distributed in the Hudson Valley.  Photo Credit:  Roberto Regalado, NYS IPM Program.

Spotted Lanternfly adult females laying eggs (ovipositing) on a “Tree of Heaven” log in the Cornell Hudson Valley Laboratory SLF colony. Two egg masses can be seen within the red ellipse. Note how well camouflaged they are, very difficult to notice at a glance if affixed on cargo or a vehicle.  Photo Credit:  Roberto Regalado, NYS IPM Program.

Why make the effort to establish a laboratory colony?  The first step in managing any pest is to understand the intricacies of its life cycle so biologists can identify ways to exploit it for management purposes.  A second point is developing the capability to produce large numbers of immature and adult insects as well as viable eggs  to provide our scientists with adequate populations of test subjects. These captive SLF can be used to evaluate the efficacy of both biological and synthetic pesticides under controlled laboratory conditions while not releasing experimental chemicals into the environment.  If certain biologicals and synthetics are identified as showing potential, then the appropriate steps can be taken in accordance with federal and NYS regulations to further evaluate their use under realistic field conditions.  If you’re interested in seeing a live view of the Spotted Lanternfly in action, please follow the link here to watch a YouTube video Public Service Announcement produced by Cornell Cooperative Extension. In the meantime, keep an eye out for this insect and if found, report it too your county’s Cornell Cooperative Extension office.  All NYS counties have an extension office, simply search the web for “Cornell Cooperative Extension” and include the name of your county for your local contact information.