Emerald ash borer This is a new beetle first identified in July 2002 as Agrilus panipennis. The beetle was found in a declining ash in southeastern Michigan. It is believed that the insect had been present in the area since about 1997 having come in on ash shipping crates. Since that time it has killed almost 8 million trees in southeastern Michigan (2 million in the last year alone).

Emerald ash borer The emerald ash borer is a close relative to the bronze birch borer (A. anxius) having similar appearance, life cycle and habits. The emerald ash borer generally has one generation per year. Adults emerge in June and July and fly to a new host. They can fly up to 6 miles (in a season), though 100 yards is more common. Eggs are laid on the bark. The eggs hatch in 14 days and the young larvae burrow into the tree. The insect over winters as mature larvae and pupates in the spring.

Emerald ash borer Infestations are difficult to detect until the tree begins to decline. Usually by this point the serpentine tunneling by the larvae has girdled the tree and recovery of the tree is unlikely. The borer attacks trees 1-inch diameter and larger. It appears to be able to successfully attack trees that are not highly stressed.

Emerald ash borer Symptoms of infestations include: Tree decline. Dieback of branches Thinning canopy Long shoots growing from the trunk or branches. Vertical cracks in trunk. D-shaped emergent holes. S-shaped tunnels under the bark filled with fine sawdust.

Emerald ash borer The quarantine area had expanded in 2003 to 13 counties. However, there are at least another 20 new infestations detected in other counties, either from the movement of infested nursery stock or firewood. There have also been new infestations in Ohio and Maryland from the movement of infested nursery stock from Michigan. A new infestation in Indiana is from the movement of firewood.

The United States solution In Ohio and Michigan they are cutting all ash trees found with D-shaped emergent holes as well as any ash found with ¼ to ½ mile of the infested tree. The cost of this is an estimated $500,000 per infested spot. Trees within 1 mile of an infestation are considered at risk – those beyond 10 miles have no concerns. Michigan is recommend treating healthy ash trees by injection with Imidaclopid (Imicide or Pointer) or Bidrin (Injecticide B). Infested trees – those showing more than 20% dieback- do not show good control with injections. Trees can also be sprayed with Carbaryl (Sevin) at the bark beetle rate.

Control steps in Michigan In addition to removing infested trees, Michigan has implemented the following. Establish a one-year moratorium prohibiting the sale and movement of ash nursery stock from, into and within Michigan’s Lower Peninsula. Ban the movement of all firewood of ANY species from the 13 quarantined counties. Fine of $100 so widely ignored. In Ohio the fine is $4000. Prohibit the movement of any ash material, unless chipper to one-inch material or less from the quarantined counties.

Michigan solution In addition Michigan is suggesting you considered planting something other than ash. A recent survey found that about 25% of all street trees in Michigan are ash. They expect to loss them all in Michigan. There is no resistance in our native ash and treatments, though effective, are expensive. Michigan considers this a wake up call to diversify the landscape.

The Canadian solution The Canadians survey found that the Eastern-most positives are all first year infestations as a result of natural spread. They are halting this spread by cutting an ash-free zone at a cost of $15 million (US). By removing all ash in this zone they hope to prevent the natural spread of the insect. All removed trees must be burned or chipped to 1-inch size or less. You can not replant ash in this zone nor can you “save” your tree by treating with pesticides. In fall 2004 EAB has been found east of the barrier. Strip about 10 miles wide

And what is at risk? The state of South Dakota contains approximately the following number of ash trees. Urban – 3.1 million Windbreak / Shelterbelt – 36 million Woodland – 7.6 million. There are almost 47 million trees at risk in our state. Michigan had a estimated 30 million ash in lower Michigan and has lost 8 million in 7 years.