WhatFinger


Children’s Gardening

Boring Beetles and Other Aliens



Late last year, forest health technician Ed Czerwinski spotted some sick-looking ash trees in northeast Toronto. Examination confirmed his fears. He had been the first to spot similar symptoms in ash trees in Windsor, southwestern Ontario in 2002. Now he knew the Asian alien had reached the nation’s largest city.

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There are 27,000 ash trees shading Toronto streets. The city’s famed ravines and parklands hold another 180,000. Added to ash trees on private property, half a million Fraxinus are at risk. The invader seems to have no common name in its home base of northern China. When Michigan scientists discovered it in that U.S. state they gave it the name of emerald ash borer. Never did they realize the appalling damage the pest can inflict. A strong flier, the female beetle lays her eggs under the bark of an ash. Within two years the tree is doomed. Upon hatching the grubs munch their way through the phloem layer just beneath the outer bark, cutting off supplies of nutrients. The emerald ash borer is far from being the first and already is not the last pest to invade the province of Ontario. Last January, just two weeks after the emerald ash borer was found in Toronto, the pyrialid moth from southern Europe was discovered in three Ontario greenhouse operations. It likes to feast on flowers, pot plants and vegetables. A year after Ed Czerwinski identified the invasion of emerald ash borer in Windsor, another Asian invader was identified, this time on the northern border of Toronto, and in adjoining neighbouring Vaughan. Mostly maples (Acer) have been affected here. Thousands of trees have been cut down in an effort to eliminate the Asian long-horned beetle. A major pest of trees in its native China, where it is named the ‘starry sky beetle,’ it is known to destroy numerous tree species, besides maples, especially poplar (Populus), willow (Salix). Other hosts include horse chestnut (Aesculus), birch (Betula), elm (Ulmus), mountain ash (Sorbus spp.), sycamore/London plane tree (Platanus), hackberry (Celtis) and silk tree (Albizia). While the Asian long-horned beetle first showed up in North America in Brooklyn, New York in 1996, its invasion of Toronto is believed to have come from carelessly shipped directly from China in wooden palettes, crates or packing materials. The emerald ash borer probably arrived in Michigan the same way. It then possibly flew across the Detroit River to Windsor. But let’s not blame the Chinese for all of our woes. Quebec City is celebrating the 400th anniversary of its founding in 1608. Two years prior to that Paris lawyer Marc Lescarbot arrived at Port Royal in Arcadia. The French are famous for their food, legalist Lescarbot no less. To that end, he landed with pigeons. They continue to poop everywhere. Another Frenchman, Leopold Trouvelot living in 19th century Cambridge, Massachusetts, decided to import a moth from Europe with which to start a silk industry. Clumsy bien-pensant, he allowed his moths to escape into the wild. And that is how the gypsy moth, a major problem for our orchards and forests, came to Canada. Thirty-five years ago, scientist Norman Myers noted that at least 250 of insect pests in the United States, accounting for one-half of all crops losses to insects, were species of foreign origin. Arriving here and facing few their natural controls, insect populations can rapidly explode. It has been calculated that if a single pair of houseflies mate in this spring, then by the end of August, if all the offspring were to live, they would be responsible for 191,000,000,000,000,000, 000 more flies. Also for the record, famous English scientist Charles Darwin showed how a single pair of cockroaches in seven months could result in 164,000,000,000 roaches . . . and a pair of elephants in 700 years in 19,000,000. This may or may not have inspired a scientist named Lubarsky to propose his Law of Cybernetic Entomology: There’s always one more bug. And there certainly is to add to the already identified 94,000 species of insects north of the Mexico border. Termites came to Toronto in 1938, believed to have arrived in scrap wood dumped near Cherry Beach jus east of downtown. Further afield, the European crane fly was found in Canada in 1955 on Cape Breton Island. Somehow from there, or perhaps again directly from Europe, it arrived in the Vancouver, B.C., area in 1965. The larvae, known as leatherjackets, devour the roots grasses, vegetables and fruit. In 1996, they were identified in the vicinity of Toronto and Hamilton, Ontario. Three years later, in March 1999, the brown spruce longhorn beetle, native to Europe and Asia, was found in dying red spruce trees in Point Pleasant Park, Halifax, Nova Scotia. Also invading us from that part of the world is the pine shoot beetle. It was first found in Ohio in 1992. The first record for the European cereal leaf beetle in Canada was reported in 1967 from southwestern Ontario. It had been reported five years earlier from Michigan and is now common throughout northeastern North America. Even pests originating in tropical and subtropical parts of the world may survive here. The sirex wood wasp that attacks pines is known from Australia and New Zealand. It was first found in upstate New York in 2004 and appears to have crossed the St. Lawrence River into Ontario since that time. All these and an amazing number of other imported pests are listed under Plant Protection Regulations 29 (2a) of Canada. Two American web sites that offer a gallery of illustrations and other information, including on invasive weeds, can be found at www.forestryimages.org and www.bugwood.org. ”I've always found insects exciting,” said Luis Buenil (1900-83), a Spanish writer and movie director. Yes, they are – but those are perhaps not exactly the words used by federal inspectors from the Canadian Food Inspection Agency (CFIA) whose job it is to try and prevent illegal immigrant pests from entering the country.


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Wes Porter -- Bio and Archives

Wes Porter is a horticultural consultant and writer based in Toronto. Wes has over 40 years of experience in both temperate and tropical horticulture from three continents.


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