Emerald Ash Borer

A new intruder has appeared in Quebec's entomological fauna. It is the emerald ash borer, a flying insect that attacks only this species of tree. It belongs to the same family as beetles. Its appearance is quite characteristic because its body has beautiful iridescent green reflections. But it's not harmless, though. No, it isn't.

The insect's larva is white in colour and digs galleries that meander through the trunks of trees. When fully mature, the adult emerald ash borer is almost half an inch long and feeds on the leaves of ash trees.

EAB arrived in North America in 2002, coming to us from Asia after travelling in pallets or shipping crates made from this species of wood. It spreads across Canada by the same means, or by being camouflaged inside firewood being moved from one region to another.

Its impacts on the ash tree

EAB is an insect pest and is not known to be a natural predator throughout North America. For this reason, the EAB is extremely difficult to eradicate.

Attacks are often pernicious as they usually occur within a single year or take up to 5 years to complete. The prognosis is usually the death of the infested plant.

The infestation proceeds roughly through 4 successive stages: 1- During 2 to 3 years, the larvae commit their deterioration most often without anyone's knowledge. 2- About 12 months later, in summer, leaves turn yellow and the foliage on the top of the trees begins to strip. 3- Another year or so and the tops become more bare and the trunk is littered with greedy people. 4- Fourth and last step, one year later: The greedy trees now proliferate, the tree barks dramatically and then gives up its last breath.

The emerald ash borer proceeds in a rather surprising manner. It starts at the top of the tree and then moves down to commit its ravages. So when it reaches the ground, there is no doubt that the attack is overly advanced.

How is such a fatal attack possible? It is largely due to the fact that the deep galleries formed by the larvae seriously compromise the sap flow of the hardwood. However, ash trees should be felled as soon as they are half affected. The period of the year when this occurs is important, as it is not appropriate to carry out the operation between March and September. The reason makes sense: it is simply the annual interval when the EAB is spreading.

What are the signs of Emerald Ash Borer?

Do you have ash trees on your property? If so, you may be most tempted to go out and look for the evil insect on your own. But you may not be aware that the signs or symptoms are sometimes very difficult to distinguish from those of diseases caused by other types of insects.

It goes without saying that a specialist not only has the know-how to eliminate the insect responsible for a particular attack, but is also aware of the treatments required in each case.

In the case of EAB, preventive intervention is possible when signs or symptoms are detected early enough. This is not easy at all, as the larvae can degrade the interior for years before the infestation becomes visibly visible.

In any case, the damage caused by the larvae appears from top to bottom and leaves wounds or signs such as bean sprouts or cracks, or a detachment or change in bark colour. These signs are almost invisible as they may appear normal to the average person. It is therefore necessary to be familiar with them to be able to recognize them.

More precisely, the larvae dig sinuous galleries inside the trunks. Once they become insects and emerge from the tree, they leave perforations (called exit holes) of about 4 mm, in the shape of a capital "D". This particular appearance is due to their rounded abdomen and flattened back.

Another potential sign is bark detachment. To feed on the larvae, squirrels remove bark and woodpeckers bite their beaks, making their characteristic holes everywhere.

A final typical clue is the pronounced abundance of samaras (the seeds of the ash tree). This effect indicates that the tree is under considerable stress.

Infestation at an early stage

A specialized protocol has been developed to find the larvae early enough despite its ability to go unnoticed. First, a branch with certain properties is selected and then the bark is removed. The time to proceed should be when the larvae are at their maximum size, i.e. during the fall or winter seasons. It is preferable to reserve this procedure for experts. In order to eliminate all traces of this invasive species, it is recommended that the tree be stumped after it has been felled.

Act early

The best way to avoid EAB attack is to not plant EAB in your home. Except that when the property contained these trees before the EAB arrived in the country, you can't do anything with them. In this case, a variety of trees should be planted for resilience.

If you are a wood-burning homeowner, be aware that EAB can hide in your cords of wood. To maximize your chances of not finding EAB, source locally.

Be aware that there are regulations from the Canadian Food Inspection Agency regarding the transportation of EAB between areas of infestation and areas where the pest is not yet present. Such movement is still possible under certain conditions.

The regulations apply to several products. Ash trees are the first to be affected, of course. The raw wood or bark of this species comes next. Then comes what is made from this type of wood: packaging material, logs, pallets or shavings... Last but not least are the vehicles used for such a load.

Repeat offenders or those who commit serious offences can receive very hefty fines. Before transporting this gasoline from one place to another, we recommend that you contact the appropriate authorities.