Emerald Ash Bore

New Weapon in Emerald Ash Borer Detection Found

The partnership of the Morton Arboretum and Illinois Parks and Recreation Association has discovered a new predator in the fight to stop the Emerald Ash Borer (EAB). Researchers confirmed that Cerceris fumipennis (Cerceris), a native wasp that preys on EAB, was found at Emerson Park in suburban Skokie. Now, researchers hope that the wasp will serve as a sort of “canary in the coal mine,” or an early warning system for EAB infestation, in areas where EAB has not yet been found, said Dr. Frederic Miller, research associate at the arboretum.

“By the time humans are able to detect EAB visually, the infestation is usually well-established. We hope this wasp will serve as an effective monitoring tool, giving us an earlier read as EAB makes its way across the country,” he said.

Researchers hope that earlier detection will help communities’ better control and manage infestations.

Cerceris wasps nest in the ground, commonly in open areas of hard-packed sandy soil with ash trees nearby. Athletic fields, such as ball diamonds, volleyball courts, horse shoe pits, and even parking lots are common nesting locations. The nests are characterized by pencil-diameter holes on top of little mounds of sand. The wasps are most active during summer months, when they feed on a whole family of wood-boring insects called Buprestid, of which EAB is a member, said Devin Krafka, research assistant at the arboretum.

“Cerceris is a parasitic wasp. It goes out to find a buprestid, or a wood-boring insect like EAB, stings it and brings one back to its nest. Later, it will lay an egg on it and place it in its own chamber. When the egg hatches, the larva will eat the beetle,” Krafka said.

To help in the hunt for the wasp, The Morton Arboretum set up a new "biosurveillance" program. The Cerceris Identification and Awareness program (CIA for EAB) enlists the help of park district staff and park users to look for wasp nests and EAB carcasses near them. The Cerceris wasp is a good candidate for this pilot program, because it doesn’t harm humans. This new program asks the community to be "citizen scientists" to help fight invasive pests.

“We need park professionals and residents to watch ball fields for signs of ground-nesting wasp activity or the actual nests,” said Edith Makra, Community Tree Advocate at the arboretum, who leads the CIA citizen science effort. “We first need to locate and confirm the presence of Cerceris so that we can enlist citizen scientists in future monitoring that can help manage EAB to protect ash trees.

518 - Emerald Ash Borer in Cincinnati

As you may already be aware, we inject the ash tree with a special solution of Emamectin Benzoate, called TREE-äge.  But how exactly is that done?

Well, we use small plugs that are placed in the trunk around the tree, and approximately six inches apart.  To do this, we drill the holes into the trunk two inches deep and close to the base, maybe a foot or two from the ground.  The plugs are then tapped into the holes, and set.  These plugs are then injected with the TREE- äge formulation.

In order to determine how many plugs to install, and how much TREE-äge to inject, the first step is to measure the diameter of the tree at 4.5 feet above the ground.  This is called Diameter at Breast Height, or DBH.  Some people are fascinated that we use a special tape measure that has the linear measurement already divided by Pi to give the diameter.

Once we have the DBH, a chart is consulted that shows how many plugs, called sites, are to be put in the tree, and how much TREE-äge per site.  As one might expect, the larger the tree’s diameter, the more sites (plugs) it needs and the more TREE-äge it needs per site.

For example, a six inch ash tree would have three sites at six milliliters of TREE-äge each, an 18 inch ash tree nine sites at nine milliliters, and a 32 inch diameter ash tree would take 17 sites at 15 milliliters per site.

The key is to get the right amount of TREE-äge into the tree.  And, under ideal conditions, the formulation will be up in the twigs in 72 hours.

The Emerald Ash Borer larvae feed on the inner bark of the ash tree.  Any larvae are exterminated by the TREE-äge formulation on contact.

This ash tree treatment has been proven effective for two years, and so we contact our clients every two years in order to renew the protection of their trees.

Emerald Ash Borer

Invasive forest pests

Emerald Ash Borer Research and Technology Development Meeting, September 26-27, 2005, Radisson Hotel, Pittsburgh, Pennsylvania : [proceedings abstracts]

An assessment of the connectivity and susceptibility of riparian ash in the southern Lower Peninsula of Michigan: Implications for the dispersal of the emerald ash borer, Agrilus planipennis (Coleoptera: Buprestidae).

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