The Asian Long-Horned Beetle: Muskoka's New Enemy Number One

By Simon Miles

The Fall of Muskoka may be about to take on a completely new meaning. Can you imagine the fall without the flaming colours of our maples and birches? Can you conceive of your favourite landscapes devoid of thousands of trees you've grown up with and taken for granted?

Unfortunately, time for imagining is fast running out. This nightmare scenario could well become a stark reality. Muskoka, and indeed much of Canada, is about to become a war zone. And every citizen has to be involved in the battle.



The enemy is the Asian Long-horned Beetle (Anoplophora glabripennis). This is an invasive species that has found its way to Toronto and Vaughan, most likely in wooden packing crates, from its native China and Korea. Although the beetle could have arrived four to six years ago, it was first identified in Canadian trees on 4th September last year in the Vaughan area. As of January this year, it had already turned up in several locales in northwest Toronto around the 400/407 interchange.

Being an invasive species, the beetle has no known natural predators, and as such constitutes a threat to the biodiversity of our natural ecosystems. Eradication is essential.

As soon as the beetle is identified, the Canadian Food Inspection Agency (CFIA) and the local officials move in to remove potential host trees within 400 metres of a sighting. Although the beetle only goes for selected hardwood trees, it does seem equally at home in many species. Thus, in some situations this can lead to the removal of 50 percent or more of the trees in a landscape, with its obvious implications for the rapid erosion of sloping land. Less obvious is the removal of habitat for the beetle's potential predators.

An alternative approach, which may well be open to us by the time you read this, is the potential use of imidacloprid. This chemical pesticide was used in the USA after sightings in 1996 in the New York area, in 1998 in Chicago and 2002 in New Jersey. There, almost 9,000 trees have been felled and more than 100,000 others have been treated with imidacloprid in buffer zones around the sightings. The pesticide is either injected into the tree or the soil, or the soil is drenched around the tree. While the advantage of pesticide use is that one keeps the treated trees, the disadvantages are several: imidacloprid is not a control agent but only a protector; its application has to be repeated every year until no sightings are reported; concentrated injections of chemicals into the environment pose threats to other species; and the financial cost is enormous.

The decision as to whether to permit the use of imidacloprid rests with the federal Pest Management Regulatory Agency. That agency is dependent upon information being compiled by the CFIA. However, whether or not we are allowed to use chemicals, what will not change is the need for action by all of us.

This is what you need to know:

1. The beetle attacks only hardwoods. The preferred host trees are: all maples; sycamore; all birches; all willows; poplar; horse-chestnut; elm; hackberry; silk tree; and mountain ash. Earlier reports incorrectly extended this preferred list to include: locust; all ashes; mulberry; plum; and pear. However, most other broad-leaved, deciduous trees are thought to be vulnerable. Richard Ubbens, Chief Forester for the City of Toronto, estimates that vulnerable trees constitute about 60 to 70 percent of the crown cover in Toronto. Among the many species being monitored are the red oak and the ashes. The ash is remarkable in that egg-laying sites have been spotted but none of these has been observed to have led to the hatching of a larva.
2. The adult beetle is a shiny bluish-black with distinctive, long, black and white antennae. The back of the beetle has white splotches. The body length, excluding the antennae, ranges from 2 to 3.5cm. The antennae are longer than the body (50% longer on the male and slightly less on the female, which also happens to be larger). The black legs have bluish sections.
   
3. Don't confuse this beetle with the White Spotted Pine Sawyer Beetle that also leaves piles of sawdust and makes similar-sized holes, but attacks only softwood trees. The Sawyer beetle has a body no more than 2cm. long, and is a dull, uniform, dark brown, except for the one white spot just behind the head.
4. The larva can reach 5cm. in length.
5. Signs of an attack are: Oval wounds on the bark (as though someone had used a potato peeler to take an eye out of the bark). The pit-like scar (generally about 1cm. long) is left as the female beetle chews through the bark to lay an egg just under the bark. One female may lay up to 100 eggs in all, with just one egg in each pit. Tree sap may be seen dripping from the wounds. Small piles of rough sawdust under the trees, from the chewing of these pits, will signal recent activity. Exit holes made by mature beetles are large enough in diameter (about 1cm.) to take a pencil. Twigs stripped of bark where adult beetles have been feeding. Wilted leaves.
6. The wounds and exit holes can appear anywhere on the tree, but are more likely to be on the trunk and main limbs.
7. The beetle prefers trees in the open or at the edges of wooded areas rather than in the interiors, so be particularly vigilant about looking for it along shorelines and roads. Although a flight of more than a kilometre has been recorded, the adult beetle is unlikely to fly more than 300 to 400 metres and tends to stay on trees that are near the one from which it first emerged.
8. The adult beetles are active and visible from early summer to mid-fall, especially from mid-morning to early afternoon on sunny days. On cloudy days, they rest in the tree's canopy. They feed on the bark of twigs.
9. The life cycle is generally about 12 months long. It starts any time from early to late summer with the female chewing away the bark to lay an egg at each site under the bark. One egg is laid each day. An egg laid in July will result in an adult beetle emerging the next July (the peak emergence time). The larva (or grub) hatches from the egg in seven to ten days and eats its way in an irregular fashion through the cambium layer, feeding on the soft phloem tissue under the bark. This is the layer that moves water and nutrients through the tree. This capability is destroyed as the larvae work their way around the tree and into the heartwood before returning to be close to the surface. The larval form exists for about 10 months. It metamorphoses into a quiescent pupa for two to three weeks. In the spring the first pupae metamorphose into adult beetles. The beetles then eat their way out to the surface.
   
10. The adult beetle is killed after 15 hours exposure to a hard frost. The larvae and pupae are known to be able to survive the winter at temperatures of minus 25 Celsius. There is debate over the egg: in Canada, it has not been found over-wintering; in the USA it has.
11. A tree can be killed within two to five years. Once dead, a tree no longer attracts the beetle.
12. Wood from felled trees should not be transported for firewood use. Although it may appear to be perfectly good wood, it has to be chipped and composted or burned to kill the eggs and larvae. Be extremely careful, especially if you live in northwest Toronto or Vaughan, where outbreaks have already occurred, not to transport any wood debris/firewood any distance at all. However, there is no danger associated with transporting softwoods or kiln-dried hardwoods.
13. If you see signs of an infestation or attack, call the CFIA at 1-800-442-2342.
14. Capture any adult beetles or larvae and keep them in a sealed jar on site.
15. The beetles pose no threat to human health and will not affect homes or workplaces.
16. For further information, go to the CFIA website at www.inspection.gc.ca.
17. More is being learned about the beetle all the time. This article's information updates earlier data published by the CFIA and will itself be subject to updates.
    

The costs of inaction could be enormous. While individuals will doubtless be motivated to act by the prospect of the loss of their everyday aesthetic enjoyment of a view, this is but one cost. In Canada, obvious losers would be tourism, the $100 million maple sugar industry, and the $11 billion forest products industry. Less obvious, but of enormous significance, is the potential disruption of the functioning of ecosystems and the provision of ecosystem services. For example, the loss of thousands of trees would remove much habitat vital for the survival of wildlife that we take for granted. Erosion of our already thin topsoils would be hastened. The contribution of those trees to the absorption of carbon dioxide would be lost. And in urban areas, such as Toronto, the loss of shade over pavement would greatly increase the production of ground-level ozone.

The earlier US experience offers three vital lessons for Canada. First, we have to act swiftly and resolutely. The US started by removing only those trees on which there had been sightings, simply because legislation did not permit the removal of trees on which there had been no such sightings. To obviate this shortcoming, the USDA obtained authority to use pesticide on trees around sightings. Last year in Chicago, some five years after the first sightings, only two trees had to be removed. The reliance on chemical pesticides was, however, heavy. Second, the US effort has been dependent upon the public for its cooperation in reporting sightings. Third, money is needed: US$138 million of federal, state and local funds has been spent on the US program to date to cover felling, chemical treatment and replanting (with some 7,570 trees having been replanted to date).

In dealing with the Toronto infestation, the City and the CFIA are hopeful that, by felling all potential host trees within 400 metres of a sighting, and by doing this during the winter when there is no adult beetle moving about, they will be able to kill off all forms of the pest. Some 14,000 trees will be removed in northwest Toronto and Vaughan. Mr. Ubbens has been very impressed and moved by the spirit of cooperation shown by the landowners involved. As he notes, in the urban areas, every tree is part of someone's everyday life. It is a heart-wrenching decision to report a tree infested and to see it, and so many around it, felled. Howard Stanley, of the CFIA, also remarks on the productive collaboration among all public sector bodies.

Residents of Muskoka, year-round and seasonal, and indeed residents throughout southern and central Ontario, will have to exhibit the same vigilance in monitoring their trees and the same commitment to the public good by reporting their findings. In addition, all of us should let our federal, provincial and local elected representatives know that we want to see sufficient public resources made available to eradicate this pest. In your calls, you should also urge that more be done to reduce Canada's vulnerability to invasive species in general. Environment Canada is coordinating the production, with the provinces and territories, of "Canada's national plan to address the threat of invasive alien species". When approved, likely in September this year, it will need money behind it. The Environment Commissioner of Ontario, in his 2003 report, has urged the provincial government to do much more to combat the threat of invasive species to biodiversity. The cutbacks in recent years have done much harm to the environment; the Asian Long-horned Beetle's presence is just further evidence of this shortsightedness in not maintaining our natural capital.

How well we fare in dealing with this beetle will also serve as an indicator of our readiness to combat other invasive species looming on the horizon. This January, the CFIA extended its wood packaging material entry controls to cover all countries of origin (other than the USA). The intent is to prevent any forest pest from being introduced into Canada. Time will tell how effective they are. Howard Stanley notes that the Brown Spruce Long-horned Beetle, an invasive species under eradication in Halifax, uses the same pathway as the Asian Long-horned Beetle and could come to Ontario. Closer to home, in Windsor, there is an infestation of the Emerald Ash Borer. This has already devastated millions of ash trees across the river in Detroit. Combating the spread of this 9 to 14 mm.-long, metallic-green beetle (with a 2.5 cm.-long larval form) is requiring the complete elimination of all ash trees in a 10 km.-wide and 30 km.-long belt around Windsor. If the clearing is not completed by April this year, there is a real possibility that the pest will spread to the rest of Ontario. There are over one billion ash trees in Ontario now and a good number of those are in Muskoka. Ironically, many were planted to replace those elms lost to Dutch Elm Disease.

The bottom line is clear: public funds have to be found fast and every individual has to commit to do their bit if we are to keep our hardwood forests.