Emerald Ash Borer

Have you ever seen this flying insect with a shimmering green body? It is a member of the beetle family and can grow up to ½ inch long. It gets its name from the fact that it preys on ash trees. As an adult, it is fond of leaves and its larva, which is white, lives in the tree and burrows into it.

The emerald ash borer is native to Asia. It arrived in North America in 2002 and has spread by traveling in the wood of crates, transport pallets or firewood.

The consequences of the emerald ash borer on a tree

This invasive insect is extremely difficult to control because on this side of the ocean it has no known predators. It kills an ash tree in five years or less, sometimes in just one year.

Gradual dieback occurs in 4 stages. The first stage is inapparent and lasts 2 to 3 years. Then, yellowing of the leaves and a beginning of thinning of the crown is noticed the following year, at stage 2. One year later, the thinning of the crown is accentuated and shoots or suckers appear. Finally, at the fourth and last stage, another year later, the suckers abound, the bark of the ash trees falls off and the tree dies.

The emerald ash borer first deteriorates the crown. When the damage reaches the ground, the attack is very severe. The galleries are then so numerous that they block the circulation of sap. As soon as the top half of a tree is affected by EAB, it must be felled. It is recommended to cut down trees between October and March.

Detecting EAB on a tree

The larvae can act for years before their damage is apparent. Their presence can be detected by a few signs or symptoms. For example, there are serpentine galleries dug by the larvae or holes of about 4 mm that look like a capital "D". The adults make these holes to exit the tree. This particular shape comes from their flat back and rounded belly. To feed on the larvae, squirrels remove bark from the tree or woodpeckers make numerous holes in the trunk. Samaras may also abound, indicating that the tree is under stress.

Early detection of the first symptoms of infestation, which first occur at the top, is essential for preventive action. These include splitting, cracking or peeling of bark due to injury to the ash tree. The bark may become discolored and leak sap. It takes an eagle eye, as the first signs are subtle.

If you have ash trees and want to detect the presence of the invader yourself to avoid costs, think again. The signs and symptoms are very similar to those of other insect pests. It is therefore essential to be familiar with them in order to detect them quickly. Call us at 579-700-0105 for advice.

The preventive stage of the disease

A technical protocol allows to detect the larvae in the tree before the first symptoms are visible. It consists of removing sections of branches with specific characteristics and debarking them. It is important to proceed during the periods when the larvae are larger and therefore easier to detect, i.e. in the fall and winter. It is best to reserve this for specialists.

The best way to prevent EAB

The safest way to avoid EAB is obviously not to plant this species. The next best thing is to diversify your planting.

You can also check your firewood for EAB. The best thing to do is to buy it locally and not to transport it (except under certain conditions) from an area regulated by the Canadian Food Inspection Agency to an uncontaminated area. More specifically, this regulation affects the transportation of ash materials, the ash trees themselves, logs, raw wood, pallets, packaging materials, ash chips or bark and even the vehicles that transport them. You can check the regulated areas at inspection.gc.ca. Failure to comply with the regulations can cost you a lot of money. Fines can be very steep, up to $15,000 for a first offence or even $250,000 for repeat or serious offences.

If the damage is not too severe, it is possible to treat the trees preventively by injecting a biological pesticide under the bark at the base of the tree every two years to kill the larvae. This protects the tree and slows or prevents the progression. But unfortunately the affected tree must be felled.

Detection of diseases and invaders

Besides the emerald ash borer, many other invaders and diseases can harm your trees. As experts, Emondage Saint-Jean will be able to give you all the assistance you need. Call us at 579-700-0105 for advice or fill out the form at the top right of this page.