How to Save Your Ash

By | Pests, Diseases & Weeds | Tags: , , , | April 30, 2012 | 3 comments

(Adapted from Melissa Williams’ blog post on the April 16 edition of the LEAF e-newsletter—and no, this is not an ad nor are we being paid for it. It’s good information.)

By now, most of you will have heard of the Emerald Ash Borer (EAB), which is infesting ash trees throughout metro Toronto, Scarborough and York Region. Unlike the scourges that affected elm trees and chestnuts, the good news is that there is an effective alternative to removal—a systemic insecticide called TreeAzin ™ which may also save you money in the long term.

There are approximately 860,000 ash trees in the City of Toronto and an estimated 2,800,000 growing in York Region. All are at risk of infestation and, if left untreated, most will succumb to this pest. This will create huge gaps in our urban forest canopy, a vital resource that cleans the air and conserves energy by shading our homes.

It is also important to remember that the larger a tree grows the more benefits it provides. It will take up to 30 years for a newly planted tree to fully take the place of a mature ash—and the cost of removing a mature tree is high.

If applied in a timely fashion, TreeAzin ™ Systemic Insecticide may be able to save your ash. This Canadian product was developed by Bioforest Technologies Inc. through the Canadian Forest Service, and is produced from an extract of Neem tree seeds—it is not Neem oil, however. It is the only effective pesticide available to control EAB in Canada, and works by being injected under the bark, where it is drawn upward with the flow of water and nutrients inside the tree. It will kill EAB larvae that feed on conductive tissues within the tree, and will also reduce the adult female’s fertility and egg viability when it feeds on the leaves of the tree. Injections are carried out in early summer, and treatment needs to be repeated every two years to remain effective (as long as the EAB is in the area).

According to the manufacturer’s website, in the year of treatment, 95 per cent of EAB larvae are killed, significantly fewer eggs are laid, and of those that are laid, 98 per cent are not viable. In the following year, larvae hatching from the few viable eggs that are laid will not complete development, and the length and number of galleries that larvae have created from feeding underneath the bark of the tree will be fewer and shorter in length, compared to those in ash trees left untreated.

Because the insecticide is injected under the tree’s bark, the treatment does not present a health risk to those carrying out the injections or to the surrounding environment. Studies show that TreeAzin ™ has low toxicity to mammals, birds, bees and other non-target species and low-to-moderate persistence in waters, soils and foliage. It is registered as a Class Four pesticide, which means it is the “least hazardous that is commercial.”

However, you need to act before the crown of the tree shows 30 per cent damage. LEAF recommends that you get quotes from at least three different registered service providers before choosing which company to hire. The cost of the treatment will depend on facts such as the size, health and location of the ash tree, but may be more affordable—even over a number of years– than the costs of removal, disposal and replacement of a diseased ash tree—not to mention the time it takes for one to grow to maturity. Additionally, this cost will be spread out over years, as opposed to one lump sum for removal.

For more information about the Emerald Ash Borer, TreeAzin ™ and licensed service providers in your area, visit the Bioforest Technologies Inc. website.

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Aldona Satterthwaite about the author: Aldona Satterthwaite

Aldona Satterthwaite started gardening as a child and has never stopped. Until recently, she was the executive director of Toronto Botanical Garden. Previously, Aldona was editor-in-chief of Canadian Gardening magazine, which during her eight-year tenure was twice named Magazine of the Year (large circulation category) by the Canadian Society of Magazine Editors. In 2007, she was co-named Editor of the Year. Aldona, who’s a Master Gardener, completed her journalism studies at the Regent Street Polytechnic (now Westminster University) in London, England and studied landscape architecture at Ryerson University. She’s enjoyed a varied and successful writing and editing career that has spanned magazines, advertising and the museum world, and has included stints as Director of Writing Services at The Museum of Modern Art, New York and as manager of creative services at the Art Gallery of Ontario.

  • Sandra Spencer

    What is killing all my spruce trees in the country? They are dying from the ground up. Is it a fungus? I cannot see any bugs and I hate to see such beautiful mature trees suddenly dying.
    A friend who is in the tree business suggested lack of water or too much shade. No that is not it. Please help.

    • Toronto Botanical Garden

      Hi Sandra, I’m sorry to hear about your spruce. I’d like to refer you to a great group, The Toronto Master Gardeners, who have a Q & A forum for gardening questions. I hope they are able to help you. Here is their address

  • lb Varie

    You mentioned: “Studies show that TreeAzin ™ has low toxicity to mammals, birds, bees and other non-target species and low-to-moderate persistence in waters, soils and foliage. It is registered as a Class Four pesticide, which means it is the “least hazardous that is commercial.” “…. which studies ?…the developer’s ones or independant laboratories ?..

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