Have you spotted a green, flying insect with a metallic green body in your ash trees? It's probably the emerald ash borer, which is so named because it ravages ash trees. This insect belongs to the same family as the beetles. Its size at maturity reaches half an inch long. Its larva is white and digs snake-like galleries in the wood of the tree. The adult feeds on the leaves.
This insect is native to Asia. It has been seen in North America since 2002. It reached us by being carried in transport material, such as crates or pallets made of ash or in firewood of this species. This is the same way it spreads from one area to another in the interior of Canada.
Its damage to ash
It is very difficult to control the Emerald Ash Borer. The reason is simple: it has no known natural predators in North America. Be aware that a tree attacked by EAB can die in less than five years; at worst, it reaches that state in a single year.
The tree's decline usually follows 4 periods. The first one takes between 2 or 3 years. Then, almost no signs that the insect is in the trees are apparent.
During the next period, about a year later, the leaves turn yellow in the middle of summer and the top of the tree is somewhat bald. A year later, chupons grow in various parts of the tree and the top has less and less leaves: this is the third period. Another year later, the chupons abound, some bark falls off and, finally, the tree dies out.
The emerald ash borer's damage begins at the top of the tree and moves downward. Once on the ground, the attack is very serious. Why is it possible to reach such a degree of aggravation? The explanation is not complicated: the larvae work deep and their galleries block the circulation of sap. This is what causes the tree to die. However, only one half attacked is enough to have to cut an ash tree. However, it is strongly recommended to avoid cutting between mid-March and the end of September, simply because this is the period during which the insect spreads.
Locating the Emerald Ash Borer
For a number of years, EAB larvae may be active without any signs of their presence being visible. But when they do become apparent, what are those signs? Galleries dug by the larvae wind their way through the interior of the tree. On the outside, holes appear through which the adults have emerged. They are shaped like a capital "D". This shape is explained by the fact that the insect has a bulging abdomen and a flat back. To gorge themselves on the larvae, the squirrels will detach the bark or the woodpeckers will perforate it with their beak. Finally, because the tree becomes stressed, its seeds, samaras, become very numerous.
It is possible to intervene preventively. However, this means that the signs or symptoms of the attack are spotted early enough. Remember, they start from the top. Sap may run down the bark and the bark may crack, split, peel or change color. But these are subtle signs, so seeing them requires a trained eye.
Do you have ash trees in your property? If so, you may be thinking that you could look for the beetle yourself. But think about it. It is quite possible to mistake symptoms or signs for EAB when they could be indicative of a completely different insect. Specialists can make the difference, and therefore, advise you on the right treatment. Unfortunately, it turns out that the best course of action is often to cut down the tree.
Preventing the disease
Not planting ash trees is the safest way to avoid being invaded by EAB. However, it is likely that you already have some on your property. In this case, it is recommended that you acquire other trees to diversify the species you have. For those who heat with wood, it would be important to check for EAB if ash is part of your wood. Ideally, you should purchase it from a local supplier.
There are regulations under the responsibility of the Canadian Food Inspection Agency regarding the transportation of ash wood from an EAB infected area to a non-infected area. Such transportation is still possible, but there are conditions that must be met. This includes ash chips or bark, logs, raw wood, pallets or other transport materials made of ash or, of course, the ash trees themselves. A first offence can result in a fine of up to $15,000, but for repeat offences or serious cases, the fine can reach $250,000. Tree bracing