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May 15, 1998 Urban Btk Spray Alert A notice in today's Chronicle Herald (May 15, 1998) announces a tree spraying program in the Halifax Regional Municipality, a so-called "Biological Insect Control Program". The spraying will take place in urban areas of Halifax and Dartmouth, starting May 26, unless there is enough opposition to stop it! They are planing to carry out periodic spraying until July 12. One of the sprays is Foray 48B - active ingredient Bacillus thuringiensis kurstaki (Btk), and it will be used against cankerworms, gipsy moth larvae, forest tent catepillars, etc. (This is exactly the same spray that is being used against the tussock moth over large rural areas of Nova Scotia this summer.) The usual line is given, namely that it is "considered harmless to humans, animals and beneficial insects such as honey bees." The claim is that this is a biological spray, but this is not true, because it also contains chemical so-called inerts. There is a very important 19-page ruling by the BC Environmental Appeal Board of April 15, 1998, which will be helpful in fighting Btk spraying anywhere. Toby Vigod was chair of the board. The ruling was that: - There was to be no aerial spraying of Foray 48B (same trade name for NS Btk spray) in the Victoria area. - Ground spraying was only to be on "appropriate deciduous vegetation", concentrating on gypsy moth "epicenters". - No spraying on school properties or open grassy areas, where children play. It was ruled that "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)." You can obtain the document APPEAL NO. 98-PES-03(b) from the following web site: http://www.eab.gov.bc.ca/pest/98pes03b.htm Below is the summary (done by David Orton) of an article from the _Journal of Pesticide Reform_, which gives the real view of this biological/chemical insecticide. Some of the inerts in past formulations of Foray 48B are also listed. Helga Hoffmann * * * * * * * * * * * * * * * * * * * * We just received a paper: "Insecticide Fact Sheet: Bacillus Thuringiensis (B.t.)", by Carrie Swadener, _Journal Of Pesticide Reform_, Fall 1994, Vol.14, No.3, pp. 13-20. It is heavily footnoted and is a survey really of the literature from a critical perspective. I found this paper extremely helpful. Here are some points from this paper which were useful for me: B.t. is "a live microorganism" or "microbial organism". Testing for the possible hazards of B.t. is conducted differently that for conventional pesticides. Microbial toxicity is described using pathogenicity (the ability of the microbe to cause disease) and infectivity (the ability of the organism to reproduce within the body.) The United States Environmental Protection Agency (EPA) requires no testing of B.t. for carcinogenicity, mutagenicity, or chronic toxicity. "Exposed people carry B.t. in their tissues." There is "a close relationship between B.t. and disease-causing pathogens": B.t. belongs to a small group of closely related Bacillus species, including B. cereus, a bacteria that is an agent of food poisoning, and B. anthracis, the pathogen of the virulent animal disease, anthrax. These three bacteria are so similar it has been theorized that they are all varieties of the same species. If B. cereus is cultured with B.t. cells, genetic material is transferred to the B. cereus cells that allows B. cereus to produce B.t.'s crystal proteins. Transfers of genetic material between B. anthracis and B.t. have also occurred. Contaminants: In the mid 1980s, several B.t. products were contaminated with other bacteria, including Streptococcus faecium and S. faecalis. While B.t. products are routinely monitored for bacterial contaminants, the risk of contamination with a disease-causing bacteria is always present. Inert ingredients: "The 'inert' ingredients are potentially the most toxic components of the formulations." These are considered trade secrets. The article gives the following very important information: Foray 48B has contained sodium hydroxide, sulfuric acid, phosphoric acid, methyl paraben, and potassium phosphate, as 'inerts.' While these ingredients make up less than 10 percent of Foray 48B, they pose hazards. Sodium hydroxide, more commonly known as lye, causes 'severe corrosive damage to the eyes, skin, mucous membranes and digestive system.... Breathing sodium hydroxide dust or mist leads in mild cases to irritation of the mucous membranes of the nose... and in severe cases to damage of the upper respiratory tract.' Sulfuric acid and phosphoric acid are both corrosive. Sulfuric acid can cause severe deep skin burns and permanent loss of vision. When inhaled as a mist, sulfuric acid may cause severe bronchial constriction, and bronchitis. Phosphoric acid is an irritant to skin and mucous membranes, and its vapors may cause coughing and throat irritation. Both methyl paraben and potassium phosphate were once registered by EPA as pesticide active ingredients. Perhaps in view of the above it is not surprising that Foray 48B is highly acidic: Foray 48B at high concentrations (about 3 percent) is acutely toxic to rainbow trout, probably because the product is highly acidic. Resistance: "Eight insect species have been studied because of their ability to develop resistance to B.t." Some examples are, the Indian meal moth, the diamondback moth, the tobacco budworm, and the Colorado potato beetle. Ecological impacts: This paper shows the impact of using B.t.k. on the ecology. But unfortunately, except for the reference above, the examples given do not directly refer to Foray 48B but to other commercial formulations of B.t.k. Some of these other formulations e.g. Thuricide, Dipel, Novabac and Futura have, in the past, been used in forest spraying operations in Nova Scotia. (See my Alternatives Dec. 1987/Jan. 1988 paper, "The Case Against Forest Spraying with the Bacterial Insecticide Bt"). The general situation is given by the following quote from Carrie Swadener's paper: Some of the most serious concerns about widespread use of B.t. as a pest control technique come from the effects it can have on animals other than the pest targeted for control. All B.t. products can kill organisms other than their intended targets. In turn, the animals that depend on these organisms for food are also impacted. Keeping in mind the above caution, the following examples are interesting: aphid-eating flies were reduced by Dipel treatment; "Dipel also has caused mortality of the cinnabar moth, used for the biological control of the weed tansy ragwort"; and "B.t. applications can disturb insect communities"; This paper shows with examples from various studies, impacts from spraying B.t. on aquatic insects and birds. David Orton, May 14/98 * * * * * * * * * * * * * * * For further information, contact David Orton, coordinator Green Web (902) 925-2514
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