Insects & Pests

Be Aware of Insects and Pests

Invasive insects and pests pose a serious threat to the trees and forests of Morris County. Some threats are well established and their damage is noticeable while others are newly emerging with their ultimate impact being unknown. Park users should be aware of these pests and their impacts when exploring the parks.

Insects and Pests

Emerald Ash Borer

The emerald ash borer (EAB) (Agrilus planipennis) is a non-native beetle that was accidentally introduced to the United States from Asia in wood packing material. The feeding habits of EAB larvae causes death to ash trees (genus Fraxinus), EAB’s preferred host.

Since its initial detection in Michigan in 2002, EAB has spread to 31 states and 2 Canadian provinces. It has killed hundreds of millions of ash trees in North America and is considered to be the most destructive and expensive insect ever to invade the United States.

EAB was detected in New Jersey in Bridgewater Township, Somerset County in May 2014. It has been found in 15+ counties including Morris County as of 2021. Morris County has the densest population of ash trees in the state, and the Morris County Park Commission (MCPC) must manage for the arrival of this pest and its anticipated impacts on the park system.

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Spotted Lantern fly

Spotted Lanternfly

Spotted lanternfly (SLF), Lycorma deliculata, is an invasive plant hopper native to Asia. As a sap sucking insect, SLF feeds by inserting their mouthparts into plant tissues. SLF are known to feed on over 70 different plant species including many crops and hardwood trees. Their feeding habits coupled with their excretions can weaken and damage plants and foster the growth of damaging mold. SLF appears to have its life history tied to (Ailanthus altissima) Tree of Heaven, an invasive tree common along roadways and disturbed areas. Throughout the year, SLF can change hosts depending on food availability.

SLF was first detected in Pennsylvania in 2014. It has since spread to a number of neighboring states and was detected in New Jersey in 2018. While the total impact of SLF is still uncertain, the variety of species it feeds on, and its swarming behavior make it a very serious pest economically, environmentally, and for people’s quality of life.

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Spongy Moth

Spongy Moth

Spongy moth (Lymantria dispar), formerly known as Gypsy Moth, is an invasive insect first brought to the United States in 1869. Spongy moth larvae, i.e. caterpillars, feed on tree leaves leading to defoliation. Defoliation can weaken trees and at times kill them outright. Due to these concerns, the MCPC in coordination with the NJ Department of Agriculture, regularly monitors for the presence of spongy moth in the parks. Larval feeding in the spring and summer and the presence of frass (droppings) are noticeable signs, as are egg masses on tree bark in the fall and winter.

Spongy moth populations are cyclic and may rise or fall from year to year. Most years no management is needed, but in years where large populations can result in extensive defoliation of trees, the MCPC may cooperate with the NJ Department of Agriculture’s annual suppression program.

Eastern tent caterpillar (Malacsoma americanum) is a native species that is often confused with spongy moth since it creates noticeable silky “tents” in tree canopies in early spring, however this species is unlikely to cause widespread damage. Below are some resources for homeowners. Park users who encounter spongy moth while in the parks are encouraged to report them to the MCPC Natural Resources Department.

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Beech Leaf Disease

Beech Leaf Disease (BLD) was first identified in Ohio in 2012 and confirmed in New Jersey in 2020. Symptoms include dark-green striped bands between leaf veins, curling and crinkling of leaves, leaf dieback and canopy thinning. Research on this relatively new disease is ongoing but at this time there is no known cure or treatment. BLD is likely to result in damage to and the eventual death of American beech (Fagus grandifolia) trees. With beech being a major component of Morris County’s forests, BLD has the potential to be very impactful. The Morris County Park Commission will continue to document and monitor the progression of this disease and is working closely with the NJ Forest Service.

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