Beetles Be Damned

Beetles have taken over Ontario — and they’ve already begun their attack on Ryerson.

An infestation of Emerald Ash Borer (EAB) beetles have killed millions of ash trees in the province, causing a stir amongst environmentalists over the past few months.

Look around Ryerson and you’ll see trees everywhere. But what’s invisible to the eye is that 10 per cent of them are already dying.

Christopher Greene, a recent PhD grad from Ryerson, based his research in integrating sustainability subsystems in the management of urban forests. He said that the beetles, which are native to Asia, tend to attack sick trees and don’t infest healthy ones. Yet, here in North America, the ash trees have not developed the genes necessary for resistance and are vulnerable.

In a battle royale worthy of Charles Darwin, the evolutionary brawl truly exemplifies the adage, “survival of the fittest.” Since these ash trees have not proliferated alongside the beetles, they have not adapted to properly defend themselves. It’s likely that the Toronto will lose most of its ash trees.

For Ryerson, this isn’t its first tree loss. “The Emerald Ash Borer is a consequence of us not learning from past mistakes,” said Greene. Before the ash trees on campus, there were American Chestnuts and American Elms that were expected to thrive in an urban setting. Unfortunately, those were lost to disease.

“Too many of them planted in urban settings in close proximity meant that that problem was exasperated, and that loss was exasperated,” said Greene. “We replaced those in a lot of urban areas with ash trees.It’s the same sort of thing — we didn’t learn those lessons from past infestations and here we are now, 80 years later, with a similar problem.”

The metallic green beetles are barely visible to anyone walking by, but upon closer inspection, they can grow up to 14 millimetres in their full adult stage. They can survive under the bark in -30 C temperatures, where they lay their eggs, which hatch larvae that suffocate the trees. They strangle them to the point where the trees cannot absorb any water or nutrients and eventually die.

It’s estimated that infested trees have five years before becoming deadwood. But with ash trees, this process occurs more rapidly, as some may die within a year if infested. It is estimated that Canadian cities will spend $2 billion over a 30 year period on the ash tree crisis.

In Toronto, treatment per tree can cost up to $300, but that doesn’t guarantee its survival. It’s expected that the city will lose most of its 860,000 ash trees by 2017. The beetles first hit Canada in 2002 in Windsor, Ont. It’s believed that the beetle may have snuck into North America by hiding in shipping containers from Asia. By 2007, the first infestation in Toronto had begun.

However, there may be a solution and it has already been approved by the federal government. The Oobius agrili, a parasitic wasp, is the beetle’s natural predator. If released, the wasps feed on the eggs and larva, eliminating any future damage on the trees. This type of damage control is referred to as biocontrol, but it too has its limitations.

“If they figure out a way to control the population of the wasps, it wouldn’t be as much of a problem as they predict,” said first-year arts and contemporary studies student, Matthew Fanson. Most students on campus lean towards an increase in biodiversity, while others don’t see an issue with just planting more trees.

Whatever may be the result, it seems that the beetles aren’t going down without a fight.

Featured image by Lucas Lucchitti