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Aerial Spraying for Gypsy Moths


It's like dropping an atomic bomb to kill a snipe.

It's standard government policy to aerial and ground spray wherever gypsy moths are found, despite the fact that a 1994 BC Ministry of Forests (MOF) Report states: "The direct impact of an established gypsy moth population on BC's natural resources would likely be small."

The biocide of choice is a combination of 2.1 percent live bacteria, Bacillus thuringiensis (Bt), and 97.9 percent unknown chemicals which are kept hidden by the Trades Secret Act. Not even a physician, who may need this information to safely treat a victim of pesticide poisoning, is allowed to know what they are. This concoction is sprayed three or four times at 10-day intervals, usually beginning in mid to late April.

In 1996, the BC Environmental Appeal Board (EAB) stopped the Bt ground spraying of four blocks in New Westminster because it caused health reactions in other areas. These included skin rash and other immune, allergic and sensitization responses such as dry, itchy skin; red, burning eyes; dry, sore throat; cough and tightness in the chest.

The Board concluded that children were at greater risk from the effects of Bt than the general population. They also noted that no studies had been done on Bt to determine long-term effects. No spraying took place in New Westminster and despite predictions of a major infestation by government officials, the gypsy moth disappeared from the area and has not returned.

Two years later, the EAB stopped the aerial spraying of Victoria due to similar concerns:

"The panel finds that aerial spraying will create an unacceptable risk of health problems among the residents of these densely populated areas. In particular, the panel agrees with the appellants that there is a risk to the health of children, people of all ages who have allergies, asthma and other respiratory ailments, people with immune deficiencies, chemical hypersensitivities and the elderly. It also poses an unreasonable adverse effect to the environment (non-target species)."

Worldwide Bans

When Bt was sprayed in New Zealand in 1997, public health nurses noticed an increase in the number of premature births and miscarriages in the spray area. There were reports of as many as five miscarriages in one street alone. One of the women who miscarried is a registered nurse. She said she began wondering whether the spray was involved in her two miscarriages when four out of five friends who were pregnant about the same time and who lived in the spray area also miscarried.

Since the spraying began in New Zealand, an unusually high incidence of hypothyroidism in children has also been reported. The Ministry of Forestry in New Zealand has confirmed that the Bt spray harmed one in six households.

Any medical dictionary will confirm that Bt is a human pathogen. In fact, it can be fatal to people using anti-ulcer drugs. A few years ago, it was the cause of an outbreak of gastroenteritis in a chronic care facility in Ontario. According to a recent Medical Post article, French scientists called for a ban on Bt after finding that inhaled spores caused lung inflammation, internal bleeding and death in laboratory mice. It also destroyed tissue in the wounds of a French soldier in Bosnia and infected wounds in immunosuppressed mice.

In the Netherlands, scientists have discovered that Bt is capable of long-term survival in the environment. They found that Bt spores reproduced in both dead and living insects. Because Bt is so similar to Bacillus cereus (a bacteria that can cause food poisoning) and Bacillus anthracis (which can cause anthrax), Dutch authorities are calling for mandatory deoxyribonucleic acid testing before the release of this pesticide. Sweden has banned aerial spraying altogether.

The Society Targeting Overuse of Pesticides (STOP) is an international, privately funded research group. Their president, Christopher Lewis, points to government statistics which show that over the past 20 years in British Columbia, 80 per cent of detected introductions of gypsy moth have died out without any control measures. He also points to the 1994 MOF report which concluded that gypsy moths pose only a minimal risk to BC trees and would likely not establish here.

"This insect should be trapped or simply left alone," says Lewis.

During the aerial Bt spraying of Vancouver in 1992, a 10 per cent sample of emergency department visits found 1,839 patients with discharges from eyes or respiratory tract; 1,352 with respiratory problems; 100 with rashes; 60 with unexplained allergic reactions; and 119 with nosebleeds. It's important to remember that the potential exists for 10 times these numbers. (There was another health report completed by the Capital Health Region in Victoria following gypsy moth spraying in 1998. However, it was decried by critics as a whitewash and did not go into the number of emergency room visits the way the 1992 study did.)

Under a 1995 directive from the US Environmental Protection Agency (EPA) workers cannot enter an area sprayed with Bt for at least four hours. And, one of the new EPA registration requirements for Bt pesticides is that workers coming in contact with the spores must wear a special respirator.

In the US it's a violation of federal law to claim that pesticides are safe when used as directed. And, a Health Canada directive has made it illegal to claim that a pesticide is "safe," "natural" or "organic."

The BC government insists that it cannot sell BC lumber internationally unless the spraying is done, regardless of human health hazards, because international markets will not accept the lumber. This policy has not been changed in recent World Trade Organization agreements.

For an in-depth analysis of Bt pesticides visit the STOP website at



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