Pest Alerts!

Spotted Lanternfly & Emerald Ash Borer
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The Emerald Ash Borer:

The Emerald Ash Borer (EAB), a non-native insect pest that kills all species of Ash trees, has now been found in Princeton as well as in surrounding counties. This highly destructive insect has killed millions of Ash trees including many trees in our area. Princeton has formulated an EAB management plan for its approximately 1,800 Ash street trees; the plan includes tree removal and selective treatment. There is growing evidence that the White Fringetree is infested by the EAB as well.

The NJDEP State Forestry Services recommends:

  • IDENTIFY Ash trees. Ash species have opposite branches and leaves and a compound leaf with 5-11 leaflets. The bark on older trees has a unique diamond-shaped ridge bark, but younger trees may have smoother bark.
  • MONITOR your Ash trees for the Emerald Ash Borer. You will know when the risk of mortality becomes urgent. Look for dying branches at the top of the tree, woodpecker damage, galleries under the bark, d-shaped holes, bark splits, sprouting at tree base and along trunk and green adult beetles.
  • USE TRAPS to detect the Emerald Ash Borer in your community or woodlot. If the Emerald Ash Borer is in the area, it will be attracted to these purple prism traps.
  • SPREAD THE MESSAGE: DON'T MOVE FIREWOOD. Visitors who bring infested firewood to second homes or campgrounds near you put your trees at risk. Use only locally sourced or certified firewood.  (More information on firewood.) 

To determine the health of your Ash trees, consult Assess Ash Trees for Emerald Ash Borer.

STC's June 23, 2016, public information session on the Emerald Ash Borer, videotaped by and courtesy of Princeton TV.

For up-to-date EAB information, consult the Emerald Ash Borer Information Network. For New Jersey, consult the NJ Department of Agriculture's EAB website.   

For more information, the following websites are helpful:

The Spotted Lanternfly: 

Now seen in Princeton, as of summer 2019, on three Ailanthus trees (Tree of Heaven). Residents are asked to report sightings by calling the New Jersey Spotted Lanternfly Hotline, 1-833-223-2840 (BADBUGO), and leaving a message with their contact information and details of the sightings or by emailing .

Residents can complete this form to register their sighting with the town arborist. We will keep a database of the information for future use. You will not be contacted unless more information is needed.

As many residents are aware, the Spotted Lantern Fly, Lycorma deliculata, has been spotted in Princeton. The Princeton arborist reports the volume of insect populations that have been seen in Princeton have been located on properties that have the Tree of Heaven; Ailanthus altissima, however the lantern fly is capable of feeding on other trees. Please see below for information pertaining to the insect.

  • Native to China, the Spotted Lantern Fly (SLF) was accidentally introduced into Pennsylvania in September of 2014, and was first detected in New Jersey in 2018. It is now also in parts of Maryland, Delaware, Virginia, and New York.
  • At this time, the SLF is NOT an insect that will cause death to healthy hardwood trees; however, they do reduce plant vigor and can become a nuisance.
  • The Lantern Fly is NOT dangerous to humans or animals; however, they do pose a threat to agriculture (specifically the grape vine) and outdoor recreation.
  • The spotted Lanternfly is a plant hopper belonging to the family Fulgoridae in the order Hemiptera.
  • Like most hemipterans, SLF feeds on plants using their sucking and piercing mouth parts to extract plant sap.
  • Adults and nymphs feed on phloem tissues of bark and young stems with their piercing and sucking mouth parts and excrete large quantities of liquid (honeydew).
  • Honeydew facilitates the growth of sooty mold and can make decks, cars, patios, and walkways a sticky mess if they are located beneath a tree with a high population of lantern flies. The sap also attracts activity from wasps, hornets, ants, and bees.
  • The preferred host is the Tree of Heaven, Ailanthus altissima. Some studies indicate that the SLF needs the Ailanthus to complete its life cycle.
  • Tree of Heaven is an invasive tree native to China that is often found on the edge of woods, rear of parking lots, edges of roads, and other areas that are not mowed regularly.
  • When crushed, the leaves of the Tree of Heaven smell like rotten peanut butter.
  • The lantern fly life cycle is 1 year. Egg masses are laid in the fall and hatch in the spring of the following year. Eggs can be laid on nearly any flat surface such as tree trunks, cars, picnic tables and houses. If the egg masses are seen, it is recommended to scrape and remove. A single egg mass can contain up to 50 eggs.  
  • Removal of host trees and their root systems is recommended by NJ and PA Departments of Environmental Protection (DEP).
  • If a property is inundated with ailanthus, DEP recommends removing all female trees, and leaving about 10% male trees to use as a host trap.
  • Tree trapping as well as organic and synthetic insecticides are available for treatment. Call your local tree care professional to develop a management plan tailored to your needs. If applying insecticides, always read the label. Only use insecticides that are registered by the EPA.

This short video, courtesy of Morris Arboretum, offers clear guidace on how to identify and remove SLF eggs:

More information can be found on the New Jersey Department of Agriculture website

Additional resources:

Spotted lantern fly description and tips

Additional Resources

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Relevant Documents

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2018 Annual Police Report22

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