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Btk
Dear Members of Council:
31 March 2008
Gentlemen/Mesdame:
Proposed Aerial Spraying with Btk
I read with dismay the recent article in The Beaver stating that the Town plans to spray certain areas of Oakville with Bacillus
thuringiensis kurstaki (Btk) in order to contain the gypsy moth caterpillars. With the introduction of the ban on the cosmetic
use of pesticides, one had hoped to breathe a little more easily this year.
However, I have done a little reading on the effects of Btk, and what I came up with has really disturbed me. I am lucky
enough not to live near to the spray zone, although I read that the spray can drift as much as a kilometer from the spray
boundaries. For those living nearer to the area in question, however, I would ask whether they are aware that, according
to www.nosprayzone.org “When Bt is sprayed (of which Btk is the kurstaki variant) it can and does infect many people
in the target zone, setting up colonies in their respiratory tract, and maybe in their intestines, that live for weeks or
months. The effects of this are not known…but it is suspected that ‘symptomless’ infections can challenge
the immune system and cause disease later…”
An article in Alive magazine states that during the aerial Bt spraying of Vancouver in 1992, a 10 per cent sample of hospital
emergency department visits found thousands of patients with discharges from the eyes, respiratory problems, rashes, allergic
reactions, or nosebleeds. Another article states that under a 1995 directive from the US Environmental Protection Agency,
workers cannot enter an area sprayed with Bt for at least four hours. One wonders, what about people – and pets - who
live in the affected areas? Staying indoors won’t help since studies have found that, five hours after spraying, the
concentrations inside buildings are higher than those outside (Journal of Pesticide Reform/Summer 2006).
Yet another article states that “When Bt was sprayed in new Zealand in 1997, a public health nurse noticed an increase
in the number of premature births and miscarriages in the spray area”. One could quote case after case, and all of them
cause for some concern.
So why take the risk? According to information found on www.earthfirstjournal.org, while Btk insecticides are formulated
from naturally occurring bacteria, when this insecticide is applied in large doses it affects the balance of nature. I think
we are sometimes lulled into a false sense of security when we see the words ‘natural,’ and ‘organic.’
What we must remember is that when we create an imbalance in nature, we set up a chain reaction which may have long-term adverse
effects.
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Naturally occurring Btk helps keep the caterpillars in balance by killing off some of them. Yes, the remaining gypsy moth
caterpillars may cause death to some of the weaker trees, but this in turn is part of nature’s cycle. We all have to
die, and the dead trees provide other uses in nature, such as leaving more room and moisture for healthy trees and providing
homes for insects. However, when we artificially apply large doses of commercial formulations of Btk - which contain a large
percentage of unknown inert ingredients - we are in danger of killing off many more Lepidoptera species than just the gypsy
moth; these may include rare butterflies on which certain plants depend exclusively for pollination and seed propagation.
Thus we help to exterminate these plants also! As for the gypsy moth, it will return, but some of its fragile sisters may
not. We have thus once more compromised the bio-diversity of a region. When we walk the trails that have been sprayed, we
can expect to find many butterfly species absent for some time to come.
Nature managed without us for millennia. If, however, the Town considers the current problem too severe to leave to nature,
can we not find some non-invasive methods of controlling the gypsy moth? Or, cannot we be patient and view this ‘epidemic’
as part of nature’s cycle. “Healthy trees can usually withstand one or two consecutive defoliations of greater
than 50 percent.” (www.na.fs.fed.us/spfo/pubs/fidls/gypsymoth/gypsy.htm)
According to a Public Health Alert (www.cow-net.com/unica/health.htm) those most at risk from being sprayed with commercial
formulations of Btk include children, those with respiratory problems, the elderly, and wildlife. Having just recovered from
a respiratory infection and being somewhat “elderly,” I need your assurance that you will not subject me to an
involuntary health risk. In his paper “The Ethics of Spraying Pesticide on Citizens Against Their Will,” Professor
Thomas Kerns cites the Nuremberg Code which says that “The voluntary consent of the human subject is absolutely essential.”
(www.nosprayzone.org/articles.kerns/)
He also mentions the operating principles of Public Health Ethics: 1) the precautionary principle, and 2) the principle of
informed consent. I personally would need far more information as to the safety of this spraying project before I would give
my consent.
As for the effects of spraying on the wildlife, what will happen to the bats and birds who rely on moths for food? What will
happen to nesting birds who are not able to find a safe place to lay their eggs, and what about non-target species of butterflies
which may be ecologically at risk?
There are so many unanswered questions and I hope to be at the information meeting on the 5 April to learn more. I also hope
that the decision to spray is not a ‘fait accompli.’
For those wishing to become more informed on this topic, there exist far more websites than the few I have cited.
Sincerely, (Mrs.) Edith Cunningham
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