Last month, the New Jersey Division of Parks and Forestry revealed plans to implement prevention measures in Passaic and eight other counties in an effort to thwart the emerald ash borer. The invasive candy-green beetle native to Asia has brought about quarantines in the 25 states where it and its voracious larvae have been detected. If left undeterred, the species threatens to eventually wipe out North America’s 16 native species of ash and New Jersey’s 24.7 million ash trees, which are thought to comprise nearly a quarter of the state’s forests.

“The Department of Environmental Protection (DEP) is committed to working closely with all of our partners to vigorously attack the spread of this destructive insect,” said DEP Commissioner Bob Martin in a recent press release. “Ash trees make up a considerable component of our forested lands. They also beautify streets, parks, and yards in hundreds of communities.”

Among the targeted parklands are Hopatcong State Park in Morris County, Swartswood State Park in Sussex County, and Ringwood State Park in Passaic County. Ringwood State Park is a 5,000-acre expanse that stretches from the heart of the heavily forested Highlands in Passaic County to the Ramapo Mountain Preserve in Bergen County, one of the six New Jersey counties where the beetles have been seen since they first arrived in the Garden State in 2014.

Plans to combat the species include monitoring through traps, ground and aerial surveillance, targeted pesticide treatment, and the deployment of parasitoids (specifically, wasps that naturally stifle ash borer reproduction), according to a recent press release from Morris County. The state formed an Emerald Ash Borer Task Force with state foresters, the New Jersey Department of Agriculture, U.S. Department of Agriculture, and Rutgers University two years ago to coordinate the effort.

“Protecting New Jersey’s trees and forests from the damaging effects of the emerald ash borer is critical to preserving our natural resources,” Assistant Director of Parks and Forestry John Sacco said. “We must take these proactive measures now to ensure the health and safety of our trees, and to those who visit our wooded areas to enjoy nature.”

The borer was first detected in Michigan in 2002, after evidently arriving in packing material from Asia. Since that time, the roughly penny-sized species has gone on to kill hundreds of millions of ash trees, primarily east of the Mississippi River. The beetle travels up to 10 miles a day, feeding on ash leaves for its brief adult life. The larvae, however, are the true borers.

After a two-week incubation period, emerald ash borer grubs coil through the phloem and outer layer of sapwood of ash trees as they feed. A tree can survive a few larvae. However, at some point, ash trees can become overwhelmed by the gouges the larvae make in their nutrient-transporting vascular system and die through a process known as girdling. After metamorphosing into bright-green bugs, the insects escape through a trademark D-shaped hole they carve in the bark, whic

h foresters use to identify the bug.

Healthy trees can be treated. However, once an infestation takes hold, it may be best to remove the tree before it dies and ultimately falls, Sacco said. Unlike in Asia, the lack of natural resistance and predators often leaves forests unable to combat the invasion in North America. Those who spot emerald ash borers or suspected evidence of related tree damage are urged to call the New Jersey Department of Agriculture at 609-406-6939 or a state DEP specialist at 609-984-3861.

Recent surveys have found the parklands being targeted by the state to be healthy, according to state officials. Still, those parklands remain vulnerable, as infestations have been known to kill a tree in three years and an entire grove in 11. Most of the state’s ash trees are found in the central and northern counties, according to the DEP.

To monitor the ash borer’s spread, the state is renewing its trapping program, which hangs scented purple, lantern-looking devices in ash-laden forests in an effort to detect the beetles. The state Department of Agriculture is seeking volunteers for trap placement this year and asking those interested to call project leader Joseph Zoltowski at 609-406-6939.

For more information on the emerald ash borer, visit emeraldashborer.nj.gov or aphis.usda.gov.

Email: zimmer@northjersey.com