May 10, 2017

Now’s the Time to Combat Emerald Ash Borer

The emerald ash borer (EAB) infestation continues to spread in the Princeton area, and time is running out for government officials and local residents to take action.

First sighted here in August 2015, the invasive beetle is expected, within three to five years, to kill all of Princeton’s approximately 2,000 ash trees if untreated С almost 11 percent of the town’s tree population.

“We are at a critical juncture in the infestation cycle,” said Princeton Shade Tree Commission (STC) Chair Sharon Ainsworth. “The time is now to decide which ash trees are candidates for treatment and to identify those that need removal this year or within the next few years.”

Also sounding the alarm, town arborist Lorraine Konopka advised, “Make a game plan. If you have ash trees that are in decent condition, you need to figure out your five-year plan. Ascertain what trees to remove and what trees to treat.”

Ms. Konopka, in conjunction with the STC, is actively engaged in identifying public trees to be treated and those to be removed. Public trees that are candidates for saving will be treated by direct injection with insecticide in the base of the tree at the roots.

“If removal is the best option,” Ms. Konopka continued, “It’s safer to remove now rather than later. The removal is more complicated and dangerous if the tree is dead.”

The STC website ( includes a guide to assist property owners in deciding which trees to remove and which to treat. It also provides a list of certified tree experts who can assist with the decision-making process, and a guide for insecticide options.

“Not making a decision is in itself a decision,” Ms. Ainsworth warned. “Untreated ash trees can be expected to die within the next few years.”

Depending on Council action, dealing with the infestation will most likely be an ongoing process, as ashes continue to die and be replaced by trees that do not host EAB, but while the STC awaits funding determination from the town, they are also seeking support from the community in battling the EAB.

The Adopt an Ash program and the town’s Tree Fund are two opportunities for individuals to help. The Adopt an Ash program, established by the mayor and Council, allows residents to pay for a licensed tree service to treat a public ash tree. The second option is a direct contribution to the Tree Fund for ash tree treatment or for the planting of new trees to replace removed trees.

The Adopt an Ash form is on the STC website and is also available at the Department of Public Works Office in Monument Hall. Contributions to the Tree Fund can be mailed to STC Tree Fund, One Monument Drive, Princeton, NJ 08540 (check payable to “Princeton”).

Costing possibly hundreds of dollars depending on the size of the tree, a treatment, which must be administered every two or three years according to Ms. Konopka, requires between $10 and $15 per diameter inch for each tree.

A collateral problem in the battle against the EAB, according to STC member Pat Hyatt, is what to do with downed trees. Healthy ash is a beautiful strong wood used to make furniture and baseball bats, and she suggests that a local mill, creative arts council or local woodworkers could devise projects to save the wood and make use of the trees that must be taken down.

Native to Asia, the EAB was first discovered in the U.S. in Detroit in 2002 and has moved east since then, killing hundreds of millions of trees. EAB adults emerge in May or early June, creating D-shaped exit holes on the branches and trunks of infested trees. They have a one-year life cycle, feeding on the ash leaf.

The fact that they first infest the top of the tree makes spotting adult beetles or exit holes nearly impossible from the ground. Woodpecker activity and damage on live trees are often early signs of EAB infestation.

Ms. Konopka pointed out that the EAB is so devastating because there is no natural resistance. There are no predators, and the beetle population grows exponentially. She added, however, that in addition to the current management plan, the town will be implementing a parasitical wasp release program, with grain-of-pepper-sized wasps that feed on the EAB larvae. In conjunction with the New Jersey Department of Agriculture and a grant from the U.S. Department of Agriculture, the program has been employed successfully to diminish EAB populations in many other states.

In emphasizing the importance of the battle against the emerald ash borer, Ms. Ainsworth explained, “The loss of our public ash trees and those on private lands will have a significant impact on our tree canopy. The STC hopes to raise public awareness of this threat so that residents can make informed choices. Trees provide not only shade and aesthetic beauty, but also produce oxygen and help sequester carbon, filter air pollution, and produce food and habitat for wildlife.”