by Paula Linquist
A 1994 BC Ministry of Forests (MoF) Risk Assessment of Gypsy Moth in British Columbia states"… the direct impact of an established gypsy moth population on BC's natural resources would likely be small." Despite this, MoF officials have applied for a Pesticide Use Permit to aerial and ground spray the Burnaby Lake area up to 4 times for gypsy moths. The biocide of choice is a combination of 2.1% live bacteria, Bacillus thuringiensis (Bt) and 97.9% unknown chemicals which are kept hidden by the Trades Secret Act.
The Society Targeting Overuse of Pesticides (S.T.O.P.) is an international, privately-funded research group. President Christopher Lewis points to government statistics which show that over the past 20 years in BC, 80 per cent of detected introductions of gypsy moth have died out without any control measures. He advocates trapping the insect, or simply doing nothing at all.
In 1996, the BC Environmental Appeal Board (EAB) stopped the Bt ground spraying of four blocks in New Westminster because it had 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, 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 immuno deficiencies, chemical hypersensitivities, and the elderly. It also poses an unreasonable adverse effect to the environment (non-target species)." [The area was sprayed by Order-in-Council in 1999 after US threats of economic embargo.]
When Bt was sprayed in New Zealand in 1997, public health nurses noticed an increase in premature births and miscarriages in the spray area. The Ministry of Forestry in New Zealand has confirmed that the spray harmed one in six households.
New Scientific Evidence
According to a recent Medical Post article, French scientists have called for a ban on Bt, after finding that inhaled spores cause 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.
A 1999 American study found that Bt may induce allergies: "With long-term exposure, affected individuals might develop asthma or other serious allergic reactions," notes the study leader.
In the Netherlands, scientists have found 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 B. cereus (a bacteria that can cause food poisoning) and B. Anthra cis (which can cause anthrax), Dutch authorities are calling for mandatory DNA testing before the release of this pesticide.
Sweden has banned aerial spraying altogether.
Bt 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 due to contaminated honey, It caused a similar outbreak in the United States. It has been isolated from infections in burn wounds; from a corneal ulcer; and from an infected finger. Commercial Bt-pesticides have been found to contain Diarrhoeal enterotoxin.
Following Bt aerial spraying in Oregon in 1991 and Vancouver in 1992, Bt. was found to have cultured in the bodies of some exposed individuals who had presented to Emergency Departments.
Under a 1995 directive from the US Environmental Protection Agency (EPA) workers cannot enter an area sprayed with Bt for at least 4 hours. 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 light of the new evidence against Bt, Robert Haward of the Soil Association which represents Britain's organic growers, says that they may have to use masks and take more care when spraying the spores on crops.
Not surprisingly, Bt has a devastating effect on other lepidoptera, which are in the caterpillar stage when spraying takes place. The Butterfly Garden in Burnaby Lake Park is likely to be severely impacted if spraying goes ahead as planned. Locally rare species in the park include the Pale Swallowtail, Western Painted Lady, Green Comma, Anise Swallowtail, Clodius Parnassian, Mustard White, and Purplish Copper.
Birds which feed on the caterpillars–warblers, chickadees and bushtits–will also be adversely affected.
Local butterfly expert Roger Ash ton calls aerial spraying "a crazy dynamite tactic which endangers every single, local, threatened butterfly habitat."
***
[From WS April/May 2000]