Why Use Green Prism Traps to Monitor Emerald Ash Borer (EAB)?

We all know that emerald ash borer (EAB) has spread throughout central New Jersey and eastern Pennsylvania, killing millions of ash trees and putting the remaining population of ash trees at high risk of infestation and death.

As of today, emerald ash borer has been found in New Jersey in Bergen, Burlington, Camden, Essex, Hudson, Hunterdon, Mercer, Middlesex, Monmouth, Morris, Passaic, Somerset, Sussex and Warren counties. It has also been found in all 67 Pennsylvania counties. (See the most current update on EAB in New Jersey and Pennsylvania)

Millions of dollars have been spent trying to control the spread of EAB, with only limited success. In urban / suburban areas like ours, part of the difficulty is a lack of pest population data – we simply don’t know exactly where EAB is and how many there are in a given location.

Collecting EAB population data is a critical component of any EAB management program. When you have limited funds and resources to attack the problem, this kind of information lets you use those resources more efficiently. Instead of guessing when and where to treat, and whether to remove or replace ash trees, you can strategically target specific locations where the pest is most prevalent and at the time EAB is most susceptible to treatments.

One of the best ways to monitor EAB populations is to use green prism traps.

green prism trap for EAB hanging in a tree

What is a prism trap?

A prism trap is a tool used to lure and trap EAB adult beetles. It’s made out of bright green corrugated plastic panels fitted together into a triangular shape and coated with a clear sticky substance that traps insects that land on it. Both male and female emerald ash borer beetles are sensitive to light in the green range of the electromagnetic spectrum, making green a good choice for the trap (purple is another good option although recent research suggests it’s not as effective as green).

Traps are baited with a substance which emits an odor that’s particularly attractive to mature EAB beetles (don’t worry, humans can’t detect it so there’s no odor from the traps).

Traps are then hung in the canopy of mature ash trees to attract beetles as they’re feeding and/or mating.

Why use prism traps for EAB?

Although we know EAB has spread throughout our area, we don’t know whether it has infested a specific property or how high the population is in a specific location.

Green prism traps help detect whether or not EAB is present, even if the signs and symptoms of an infestation are not apparent. If emerald ash borer has been identified within 15 miles of your location, it’s a good idea to hang sticky traps on your property. By getting an early warning of EAB activity from the traps, treatment can be administered on a timely basis to improve the chances of successfully saving your ash trees.

Once EAB is detected in an area, prism traps provide data needed to reduce EAB management costs and improve treatment efficacy. The beetle population isn’t uniform throughout an area; while some locations may have a very low population, nearby locations could have a high rate of EAB infestation. Using prism traps helps to identify low, moderate and high population areas to help guide treatment and removal decisions.

For example, while EAB treatments (using TreeAzin) are typically done every second year, a high population of adult beetles in the area would necessitate retreating ash trees after only one year.

Data from EAB prism traps can also help determine the age of an infestation in a given area. Treatment with TreeAzin should be done back-to-back in years 7/8 and 10/11 of an EAB infestation, rather than every second year. Without sticky traps, it would be difficult to properly time these treatments.

Where are green prism traps placed?

The traps are hung in the canopy of ash trees, about 15 to 20 feet above the ground. They should be placed toward the outside edge of the canopy, away from the trunk and exposed to sunlight.

The branch must be strong enough to support the trap and have enough clearance to let the trap hang freely (this might require some pruning before the trap can be hung).

When should prism traps be hung in trees and/or removed?

Green prism traps should be hung before adult EAB beetles emerge in spring. In our area, that’s typically in May.

Traps are taken down after the EAB adult flight period, which is usually toward the end of August.

How are EAB traps monitored?

Traps are removed from the tree and visually inspected for signs of emerald ash borer beetles. It takes a practiced eye to spot the dead beetles amongst all of the other insects, leaves, and debris that has stuck to the glue-like surface.

It’s also a good idea to check the traps regularly (at least monthly) to make sure they’re still intact, that the sticky surface isn’t completely covered in dirt or debris, that the glue hasn’t worn off and that the bait is still in place.

How can I set up a green prism trap to monitor EAB on my property?

Generally speaking, this isn’t something a property owner should handle themselves. Not only are traps not readily available to consumers, but they can be difficult to hang properly without the right equipment and the data gathered isn’t helpful without the training and experience to interpret it.

That’s why Organic Plant Care LLC offers a green prism sticky trap service for property owners in our service area. The service includes installing 2 traps per property (typically in May), monitoring and recording activity monthly through the trapping season (until August), and recommending treatment or removal options based on the results.

This is the most effective and efficient way to improve treatment outcomes and minimize your EAB management costs.

Contact us today at 908-309-6611 for a free consultation to see if an EAB prism trap program is right for you.

Bill Grundmann

Bill is the owner of Organic Plant Care, LLC. He takes an integrated approach to tree care, focusing not only on the trees themselves but also on the surrounding environment, managing tree health from the "ground up" - healthy soil equals healthy plants. Bill is a New Jersey Licensed Tree Expert and NJ Approved Forester with over 35 years of experience in the tree care industry.