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Emerald ash borer: symptom and treatment

Agrile du frêne - Émondage SBP

Spring is the time of year when everything seems to revive. The heat is back, the flowers begin to bloom while the trees adorn themselves with their most beautiful foliage. But, spring is also a pivotal period for the emergence of the emerald ash borer. What are the signs and symptoms indicating that your tree is contaminated with the borer? Is there a treatment to counter this infestation? That’s what we’ll examine together.

What is emerald ash borer?

A small insect in the Coleoptera family, the emerald ash borer is an highly destructive exotic Asian metallic blue-green color insect of about 8.5 to 14mm. Feeding on the leaves and the living part of ash trees, the emerald ash borer is a real scourge for this species of tree which is more and more affected every year. Since its appearance in the 2000s, this insect has already decimated millions of ash trees on Canadian soil.

The emerald ash borer and its spread

The emerald ash borer spreading principle is very simple. After growing for a year or two, the adult insect emerges from the tree forming a D-shaped hole. Usually emerging between May and the end of August, the adult borer will first attack the tree from which it has emerged by laying eggs on its sides before going to contaminate the other ash trees nearby. If the adult insect causes the destruction of the foliage and bark of the tree, it is mostly the larvae from the laying that cause the most damage.

In fact, once the eggs have hatched, the larvae penetrate into the living part of the tree, that is just under the bark, by digging numerous S-shaped tunnels in order to feed from the living part of the tree. In so doing, the larvae deprive the ash tree of the minerals and sap it needs to grow, which gradually causes its death. Once the larvae have reached maturity, the adult borer leaves the tree and the cycle begins again until the tree can no longer ensure the survival of the larvae.

Signs and symptoms of ash attacked by the borer

If the damage caused by the borer is almost imperceptible at the very beginning since the insects first attack the leaves, the ravages quickly become visible when these insects interfere under the bark. But when these signs become visible in the trunk of the tree, the state of infestation is very advanced and it is often too late to save the tree.

The signs

– Galleries in an S-shaped pattern are visible under the bark
Presence of D-shaped exit holes (formed when adult insects emerge from the tree)
– Presence of woodpeckers and squirrels feeding on larvae under the bark – Food notch on the leaves eaten by the borer

The Symptoms
– Yellowing of the leaves
– Presence of sprouts, that is to say the growth of new adventitious shoots on the trunk and branches of the tree
– Split bark

Treatment and felling procedure

With few natural enemies resilient to our Quebec winters, the emerald ash borer is a formidable and persistent insect. Although many studies are trying to find a way to eradicate this harmful species, there are currently few treatments to counter the spread of the borer.

Developed by the Canadian Forest Service (CFS), TreeAzin is currently the most used product to stop, or at least slow down, the spread of this pest. A biopesticide based on azadirachtin, a molecule derived from neem seeds, TreeAzin is a liquid spring capsule treatment that is inserted at the base of the tree. By proceeding this way, the sap, full of this biopesticide, distributes the product throughout the tree thus significantly decreasing the growth of the borer. For the treatment to work, the tree must not be too damaged and TreeAzin injections must be done between June 1st and August 31st.

If your tree is much too ravaged to be preserved, it is imperative to fell it. But beware, you can not fell the tree yourself! In order to avoid further spread of the borer, you must entrust your ash tree to a pruning company, such as Émondage SBP company, which will be responsible for handling and safely transporting the contaminated wood in accordance with the standards and requirements of the Canadian Food Inspection Agency (CFIA). It is also important to note that it is forbidden to use wood from the cutting of a contaminated ash as firewood.

Moving EFI contaminated wood outside a restricted area can lead to serious penalties. For example, you can not bring logs of infested ash from your cottage to your city house for firewood. Under the Plant Protection Act, a penalty can be imposed on offenders in the form of a fine of up to $ 15,000.

Call on a certified company

You are concerned that your ash tree is infested with the borer. You have noticed some signs of decay, but you are not sure. Use a specialized company such as Émondage SBP for expert advice to determine if it is possible to treat your tree or if it is best to cut it down. When it comes to taking care of your trees, or getting rid of them properly, quickly and safely, Émondage SBP is here to serve you.