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Canada's trees: Budworm infestation and DDT
It begins as a tiny stowaway on a crate from Europe or Asia, a relocated piece of firewood, or just a mild winter. Within decades, millions of hectares of Canada's woodlands have been laid waste because of it. Armies of tiny insects have stripped city boulevards of stately elms and ruined billions of dollars worth of softwood. Since the 1950s, science has fought these invading waves of caterpillars and beetles using everything from DDT to pheromones and bacteria. But victory seems no closer in the fight to save Canada's trees.
• Infested fir trees take on a reddish colour because dead needles are stuck to the tree with strands of silk. The needles are washed or blown off in the fall, leaving the trees a greyish colour. Eventually the branches and treetops are killed off and the trees die.
• Known outbreaks of spruce budworm date back as far as 1704. Outbreaks occur an average of 29 years apart.
• Few synthetic pesticides existed until after the Second World War. DDT (dichlorodiphenyltrichloroethane) was the first, and was hailed as a breakthrough in the war against bugs. Swiss chemist Paul Hermann Müller won the 1948 Nobel Prize for Physiology or Medicine "for his discovery of the high efficiency of DDT as a contact poison against several arthropods."
• A 1948 CBC Radio Ontario School Broadcast episode presented a drama "about the wonderful insecticide DDT." Young Johnny is having a problem with potato bugs, and borrows a bucket of DDT from kindly Mr. Martin. "It worked like a miracle!" Johnny exclaims.
• Environmental problems related to extensive pesticide use were discovered in the 1950s and 1960s, including the poisoning of fish and birds, and toxic contaminants that remained in the environment for years, becoming more concentrated as they move up the food chain. The perils of DDT were made famous in American biologist Rachel Carson's 1962 book Silent Spring.
• High levels of "persistent organic pollutants" like DDT can disrupt the body's neurological, reproductive and immune system.
• In 1956 a simmering battle between New Brunswick fish and forest conservation groups over insecticide use broke wide open. A report revealed that a stray DDT spray plane killed 825,000 hatchery salmon and trout. The Miramichi salmon count had been declining for years, ever since budworm spraying began.
• Fishing groups questioned the logic of spraying to protect one natural resource only to damage another. Foresters countered by saying that good fishing rivers require a healthy forest cover.
• In May 2001, Canada signed the Stockholm Convention on Persistent Organic Pollutants, which bans 12 of the world's most dangerous chemicals, including DDT. The convention was signed by 50 nations and is legally binding as of May 17, 2004.
• DDT is still used in many developing countries as the cheapest and most effective way of fighting the spread of diseases such as malaria. Travelling by wind and water, the toxins can travel as far as the Canadian north, where they have been found to poison fish and animals eaten by the Inuit. According to Environment Canada's 1997 Canadian Arctic Contaminants Assessment Report, some Inuit women have been found to have high levels in their breast milk.
Program: Newsmagazine
Broadcast Date: July 7, 1957
Guest(s): Charlie Abcock, Pat Cornapatnickie, Earl Fitzgerald, Mike Gordie, Bob Yeats
Reporter: Kingsley Brown
Duration: 8:51
Last updated: February 3, 2012
Page consulted on May 10, 2013
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