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Date: 2 Jan 1999 15:47:52 -0600
Dear People - this is a longish piece, but our being opposed to having Bt genetically engineered into our food requires that we know what we're talking about, as well as be able to refer to scientific studies backing us up. Bt is presented as "practically non-toxic," and here's evidence with which to fight that supposition. This piece is excellent, but does anyone have more uptodate stuff on Bt and its variants' effects on us when we consume it in G-E food?
Have a Great Anti-G-E Activity Year,
Nancy Oden, Jonesboro, Maine, USA
Northwest Coalition for Alternatives to Pesticides
P.O. Box 1393 Eugene, OR 97440
Phone: (541) 344-5044
** Pesticide Action Network North America (PANNA) **
Phone: (415) 541-9140 | *For general information
Fax: (415) 541-9253 | about PANNA, send an
email: firstname.lastname@example.org | email message to email@example.com
by Carrie Swadener
Mode of Action
Factors Affecting Selectivity
Health Effects Testing
Laboratory Tests of Acute Toxicity
Acute Toxicity to Humans
Special Concerns about B.t. Toxicity
B.t.'s Ecological Impacts
Bacillus thuringiensis (B.t.) is a live microorganism that kills certain insects and is used to kill unwanted insects in forests, agriculture, and urban areas.
In a purified form, some of the proteins produced by B.t. are acutely toxic to mammals. However, in their natural form, acute toxicity of commonly-used B.t. varieties is limited to caterpillars, mosquito larvae, and beetle larvae. B.t. is closely related to B. cereus, a bacteria that causes food poisoning and to B. anthracis, the agent of the disease anthrax. Few studies have been conducted on the chronic health effects, carcinogenicity, or mutagenicity of B.t. People exposed to B.t. have complained of respiratory, eye, and skin irritation, and one corneal ulcer has occurred after direct contact with a B.t. formulation. People also suffer from allergies to the "inert" (secret) ingredients. People with compromised immune systems may be particularly susceptible to B.t.
Viable B.t. spores are known to exist for up to one year following application. Insect resistance to B.t. has been well documented. Genetic engineering may greatly expand use of B.t., speeding up the development of more resistance.
Large-scale applications of B.t. can have far-reaching ecological impacts. B.t. can reduce dramatically the number and variety of moth and butterfly species, which in turn impacts birds and mammals that feed on caterpillars. In addition, a number of beneficial insects are adversely impacted by B.t.
B.t. is less toxic to mammals and shows fewer environmental effects than many synthetic insecticides. However, this is no reason to use it indiscriminately. Its environmental and health effects as well as those of all other alternatives must be thoroughly considered before use. B.t. should be used only when necessary, and in the smallest quantities possible. It should always be used as part of a sustainable management program.
As hazards of conventional, broad acting pesticides are documented, researchers look for pesticides that are are toxic only to the target pest, have less impact on other species, and have fewer environmental hazards. Bacillus thuringiensis (B.t.) insecticides result from this research. However, there is evidence suggesting that B.t. is not as benign as the manufacturers would like us to believe, and that care is warranted in its use.
B.t. is a species of bacteria that has insecticidal properties affecting a selective range of insect orders. There are at least 34 subspecies of B.t.(1) (also called serotypes or varieties) and probably over 800 strain isolates.(2) B.t. was first isolated in 1901 in Japan from diseased silkworm larvae. It was later isolated from Mediterranean flour moths and named Bacillus thuringiensis in 1911.(3) It was not until 1958 that B.t. was used commercially in the United States.(4) By 1989, B.t. products had captured 90-95 per cent of the biopesticide market.(5)
Bacillus thuringiensis products available in the United States are comprised of one of five varieties of B.t.: B.t. var. kurstaki and var. morrisoni, which cause disease in moth and butterfly caterpillars; B.t. var. israelensis which causes disease in mosquito and blackfly larvae; B.t. var. aizawai which causes disease in wax moth caterpillars); and B.t. var. tenebrionis, also called var. san diego, which causes disease in beetle larvae.(6,7) Other strains of B.t. have been discovered that exhibit pesticidal activity against nematodes, mites, flatworms, and protozoa.(5)
B.t. products are used to control moth pests in fruits, vegetables, and beehives; blackfly and mosquito pests in ponds and lakes; and several beetle pests in vegetables and shade trees.(6)(See Fig. 1,2, and 3 for more details.) Common brand names include Dipel, Foray, Thuricide (all B.t. kurstaki), Vectobac, Mosquito Attack (all B.t. israelensis), and M-Trak (B.t. tenebrionis).(6)
When conditions for bacterial growth are not optimal B.t., like many bacteria, forms spores. Spores are the dormant stage of the bacterial life cycle, when the organism waits for better growing conditions. Unlike many other bacteria, when B.t. creates spores it also creates a protein crystal. This crystal is the toxic component of B.t..
After the insect ingests B.t., the crystal is dissolved in the insect's alkaline gut. Then the insect's digestive enzymes break down the crystal structure and activate B.t.'s insecticidal component, called the delta-endotoxin. The delta-endotoxin binds to the cells lining the midgut membrane and creates pores in the membrane, upsetting the gut's ion balance. The insect soon stops feeding and starves to death.
If the insect is not susceptible to the direct action of the delta-endotoxin, death occurs after B.t. starts vegetative growth inside the insect's gut. The spore germinates after the gut membrane is broken; it then reproduces and makes more spores. This body-wide infection eventually kills the insect.(8)
One of B.t.'s most desirable characteristic is its selectivity; only certain insects are susceptible to the delta-endotoxin. Scientists have identified at least 29 different crystals and delta-endotoxins.(5) Each is effective against specific insects. Each variety of B.t. can produce one or more of these toxins.(7) Alkaline (basic; pH greater than 7) solutions activate the delta-endotoxin, and different varieties may require different pHs.(9) Certain enzymes must also be present in the insect's gut to break the crystal into its toxic elements.8 In addition, certain cell characteristics in the insect gut encourage binding of the endotoxin and subsequent pore formation.(7) The age of the insect is also a factor, the younger larvae being more susceptible than older larvae.(8)
Since B.t. is a live 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.(10)
Each of the more than 800 strains of Bacillus thuringiensis may exhibit different toxicity to insects, rodents and humans. This fact complicates any discussion about the toxicity of B.t. The following are summaries of the acute toxicity data available for two commonly used commercial varieties of B.t..
Bacillus thuringiensis var. kurstaki (B.t.k.): B.t.k. and commercial products containing B.t.k. generally have low oral acute toxicity to rats. In tests with laboratory animals, researchers did not observe any adverse effects after feeding large doses.(11-13)
Other types of exposures have some acute effects. Rats who breathed air containing B.t.k. spores experienced respiratory depression,(14) and B.t.k. spores injected into rats' veins aggravated preexisting disease.(15) Both B.t.k. and Foray 48B are irritating to rabbit skin,(16) and Foray 48B is moderately irritating to rabbits' eyes.(12)
Bacillus thuringiensis var. israelensis (B.t.i.): In studies assessing B.t.i.'s acute toxicity to mammals, mortality only occurred when B.t.i. was injected into the abdomen or the brain. In one study conducted on rats, 79 percent mortality occurred after a single injection into the brain.(17) Effects other than mortality can also occur. For example, in mice injected with a B.t.i. suspension, spleens became enlarged.18
B.t.i. is irritating to both eyes and skin. Injection of both viable and inactivated B.t.i. spores under the skin resulted in abscesses in mice.(17) Rabbits' eyes are irritated by B.t.i.(18) The irritancy of B.t.i. to eyes depends on the physical characteristics of the formulation; a dry, dusty formulation with smaller particles is less irritating and cleared from the eye more quickly than a clumped formulation with larger particles.(17)
In a purified form, B.t.i.'s endotoxin is clearly toxic to mammals. When the delta-endotoxin from B.t.i. was injected intravenously into mice, they exhibited rapid paralysis, followed by death within 12 hours. When the same dosage was injected under the skin of suckling mice, death occurred in 2-3 hours. The delta-endotoxin also caused destruction of rat, mouse, sheep, horse, and human red blood cells.(19) When a small protein isolated from the endotoxin was administered to mice at sublethal levels, mice suffered from severe hypothermia and their heart beat slowed.(20)
Bacillus thuringiensis var. kurstaki: There have been few experimental studies assessing the toxicity of B.t.k. to humans. Most information comes from occupational exposures, or from exposures occurring during large-scale B.t.k. programs.
One case of B.t.k. infection resulted from a farmer splashing a B.t.k. formulation, Dipel, in his eye. The man developed an ulcer on his cornea from which positive B.t.k. cultures were taken.(21) Another man working on a spray program splashed B.t.k. on his face and eyes. He then developed skin irritation, burning, swelling, and redness. B.t.k. was cultured from a sample taken from his eye.(22) Ground-spray applicators using Foray 48B reported symptoms of eye, nose, throat, and respiratory irritation. The frequency of their complaints was found to be related to the degree of exposure. Workers with similar preexisting health problems were more likely to report adverse effects from the ground spray.(23)
A woman exposed to an B.t.k. formulation as a result of drift went to the hospital due to burning, itching and swelling of her face and upper chest. She later exhibited a fever, altered consciousness, and suffered seizures.(24) No B.t. was cultured from tissue samples, but her doctor believed that B.t. was the cause of the clinical symptoms.(25)
Monitoring studies following large-scale B.t. spray programs have shown that exposed people carry B.t. in their tissues. For example, more than 11 percent of nasal swab samples taken from patients surveyed by doctors in Vancouver (Canada) following a gypsy moth spray program were found to contain B.t.k.(23) B.t. was also found in cultures taken from patients in Lane County, Oregon following a gypsy moth spray program there. Monitoring studies also show that exposed people report a variety of health problems that they believe to be associated with B.t. exposure.(22) For example, during the Vancouver spray program, almost 250 people reported health problems, mostly allergy-like or flu-like symptoms. During a Washington gypsy moth spray program, over 250 people reported health problems and 6 were treated in emergency rooms for allergy or asthma problems.(26) Physicians have so far been unable to definitively link B.t. exposure to these health problems.(22,23,26)
Bacillus thuringiensis var. israelensis: There has only been one case of documented adverse effects of B.t.i. on humans. This case involved a researcher who accidentally injected himself with a mixture of B.t.i. and another kind of bacteria commonly found on human skin.(20) He suffered from a toxic reaction and irritated lymph vessels. When these two bacteria were later injected into rodents the combination was consistently lethal, but each bacteria injected separately caused only slight inflammation.(8)
Exotoxins: The earliest tests done regarding B.t.'s toxicity were conducted using B.t. var. thuringiensis, a B.t. strain known to contain a second toxin called beta-exotoxin. The beta-exotoxin is toxic to vertebrates, with an LD50 (median lethal dose; the dose that kills 50 percent of a population of test animals) of 13-18 milligrams per kilogram of body weight (mg/kg) in mice when injected into the abdomen. An oral dose of 200 mg/kg per day killed mice after eight days.20 Beta-exotoxin also causes genetic damage to human blood cells.(27) B.t. formulations containing beta-exotoxin have not been used in most countries(20) although attempts are currently being made to register beta-exotoxin as an insecticide in the United States.(8) Another toxin produced by B.t. is the alpha-exotoxin that is highly acutely toxic to mice.20 Current B.t. production methods are such that alpha- exotoxin is not a "significant component" of B.t. formulations.(8)
Related Bacteria: 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.(28,29) 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.(28) Transfers of genetic material between B. anthracis and B.t. have also occurred.(30)
A toxin produced by B. cereus that causes diarrhea in monkeys is also produced by certain strains of B.t.,(30) although this toxin is not likely to be present in B.t. spore formulations.(28) Human volunteers suffered from nausea, vomiting, diarrhea, colic-like pains, and fever after eating food contaminated with one B.t. strain, B.t. var. galleriae.(31) These examples indicate the close relationship between B.t. and disease-causing pathogens.
Increased Susceptibility: People with compromised immune systems or preexisting allergies may be particularly susceptible to the effects of B.t. In mice with reduced immune function, the dose required to kill more than 50 percent of the mice when injected was several orders of magnitude smaller than the highest dose tested in normal mice.(32) Mice with impaired immune function also showed higher mortality than regular mice when one dose of B.t.i. was injected into the abdominal cavity.(33) Although no definite cases have been reported of B.t. infecting humans with compromised immune systems, the Oregon Health Division suggested before a B.t.k. spray program that "individuals with...physician-diagnosed causes of severe immune disorders may consider leaving the area during the actual spraying."(34)
A memo from Novo Nordisk, the manufacturer of Foray 48B, states that the amount of the spray a person would be exposed to would be too small to develop new allergies. However, "It is possible that someone that already has developed an allergy to one of the components of Foray 48B or has asthma I could be affected by exposure to small quantities of Foray 48B."(35) The 1991 Material Safety Data Sheet for Foray 48B states "Repeated exposure via inhalation can result in sensitization and allergic response in hypersensitive individuals."(36)
Contaminants: In the mid 1980s, several B.t. products were contaminated with other bacteria, including Streptococcus faecium and S. faecalis.(37) While B.t. products are routinely monitored for bacterial contaminants,(2) the risk of contamination with a disease-causing bacteria is always present.(25)
All B.t. products contain ingredients other than B.t.. These are identified only as "inert" ingredients and are called trade secrets by the manufacturers of the products. The "inert" ingredients are potentially the most toxic components of the formulations.(8) For example, during the 1992 Asian gypsy moth spray program in Oregon, a woman who was exposed to Foray 48B had a preexisting allergy to a carbohydrate that was present as an inert ingredient. Within 45 minutes of exposure, the woman suffered from joint pain and neurological symptoms.(38)
Because "inerts" are called trade secrets, there is little public information about their identity, but the information that is available indicates they could cause health problems. Foray 48B has contained sodium hydroxide, sulfuric acid, phosphoric acid,(39) methyl paraben,(40) and potassium phosphate,(41) as "inerts." While these ingredients make up less than 10 percent of Foray 48B,(39) 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."(42) 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.(43) Phosphoric acid is an irritant to skin and mucous membranes, and its vapors may cause coughing and throat irritation.(43) Both methyl paraben and potassium phosphate were once registered by EPA as pesticide active ingredients.(44)
Sodium sulfite has been identified as an inert ingredient of the B.t.k. formulation Dipel 8AF.(45) Up to ten per cent of asthmatics (about one million people in the United States) may react to sulfites, particularly those people who are treated with steroids.(42) Symptoms of exposure in those sensitive to sulfites usually involve the respiratory system, and can also include nausea, diarrhea, lowered blood pressure, hives, shock, and loss of consciousness.(42)
Very little is known about the natural ecology of B.t. It occurs naturally in many soils. In one study, B.t. was isolated from 70 per cent of soil samples taken from around the world, and was most abundant in samples taken in Asia. More than half of these isolates were undescribed varieties of B.t.(46) B.t. has also been isolated from insect bodies, tree leaves and aquatic environments.(7) It has even been recovered from paper.(47)
Soil: B.t. generally persists only a short time in soil. The half life of the insecticidal activity (the time in which half of the insecticidal activity is lost) of the crystal is about 9 days.(48) However, small amounts can be quite persistent. In one experiment, B.t. spore numbers declined by one order of magnitude after 2 weeks, but then remained constant for 8 months following application.(49)
B.t. does not appear to move readily in soil. In one study, two varieties of B.t. were applied in adjacent plots, but did not become cross-contaminated, indicating that B.t. does not move laterally in soil.(2,8) Other studies found that B.t. was not recovered past a depth of 6 centimeters after irrigation, and that movement beyond the application plot was less than 10 yards.(7,50)
Foliage: B.t. deposited on the upper side of leaves (exposed to the sun) may remain effective for only 1-2 days, but B.t. on the underside of leaves (i.e. protected from the sun) may remain active for 7-10 days.(2,8) It is possible for it to be significantly more persistent, however. Viable spores of B.t.k. were recovered from white spruce foliage one year after application.(51) In one experiment conducted in Japan, B.t. persisted for two years in a citrus orchard and remained toxic to caterpillars.(52)
Water: B.t.k. has been recovered from rivers and public water distribution systems after an aerial application of Thuricide 16B. Standard water treatment processes are not adequate to destroy B.t.k. spores.(53)
B.t.i. spores and crystals bind readily to sediments in the water column,(54,55) which reduces their efficacy by making them inaccessible to mosquito and blackfly larvae.
In one test, B.t.i. was applied to water, then allowed to contact mud particles. Over 99 percent of the B.t.i. spores were found in the mud, rather than in the water, after 45 minutes. The B.t.i. retained viability and toxicity for at least 22 days, killing 90 percent of the mosquito larvae when the mud was stirred and reintroduced to the water column.(54)
In another experiment, viable cells were recovered from the water for up to 200 days and in the sediment for up to 270 days after application.(55)
Air: B.t.k. has been found to drift over 3,000 meters downwind during an aerial application. The distance B.t.k. is capable of drifting depends upon the amount and method of application,(56) as well as the climatic conditions. B.t. thuringiensis was measured in air for up to 17 days following an application.(4)
Examples of genetic manipulation and genetic engineering with B.t. include the following:(7)
Clearly, the possibilities for the genetic engineering of B.t. delta-endotoxins seem endless. However, researchers know so little about the ecology and genetic stability of B.t., that the potential ecological effects of these transgenic organisms are impossible to predict with certainty.
Scientists once thought that the mode of action of B.t. was complex enough to prevent the development of pest insect resistance. However, time and further research proved this to be untrue. Eight insect species have been studied because of their ability to develop resistance to B.t.(57) The Indian meal moth, a pest of grain storage areas, was the first insect to develop resistance to B.t.k.(58) in laboratory experiments. Resistance progresses more quickly in laboratory experiments than under field conditions due to higher selection pressure in the laboratory.(59) No indications of insect resistance to B.t. were observed in the field, until the development of resistance was observed in the diamondback moth in crops where B.t. had been used repeatedly.
Since then, resistance has been observed in the laboratory in the tobacco budworm, the Colorado potato beetle and other insect species.(57) The gypsy moth also shows potential for developing B.t. resistance.(60) Some insects, such as the diamondback moth and the tobacco budworm, exhibit resistance to multiple B.t. strains.(61,62) Development of resistance occurs faster when larger amounts of a pesticide are used, so that use of crop plants genetically-engineered to produce the B.t. toxin could dramatically increase the number of B.t.-resistant insects.
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.
Beneficial insects: Many insects are not pests, and any pest management technique needs to be especially concerned about those that are called beneficials, the insects that feed or prey on pest species. B.t. has impacts on a number of beneficial species. For example, studies of a wasp that is a parasite of the meal moth (Plodia interpunctella) found that treatment with B.t. reduced the number of eggs produced by the parasitic wasp, and the percentage of those eggs that hatched.(63) Production and hatchability of eggs of a predatory bug were also decreased.(63) On collards, aphid-eating flies in the family Syrphidae were reduced by Dipel treatment.(64) Both B.t.tenebrionis and Dipel have caused mortality of predatory spider mites.(65) Dipel also has caused mortality of the cinnabar moth, used for the biological control of the weed tansy ragwort.(66) Finally, B.t.i. has caused mortality of a moth (Synclita obliteralis) that helps control aquatic weeds in Florida.(67)
Other insects: Many insects that do not have as directly beneficial importance to agriculture are important in the function and structure of ecosystems. A variety of studies have shown that B.t. applications can disturb insect communities. Research following large-scale B.t. applications to kill gypsy moth larvae in Lane County, Oregon, found that the number of oak-feeding caterpillar species was reduced for three years following spraying, and the number of caterpillars was reduced for two years.(68) Similar results were found in a study of caterpillars feeding on tobacco brush following a B.t.k. application to control spruce budworm in Oregon.(69) In untreated areas, the number of species was about 30 percent higher, and the number of caterpillars 5 times greater, than in B.t.k.-treated areas two weeks after treatment. The number of caterpillars was still reduced in treated areas the following summer.
In Washington, B.t. applications in King and Pierce counties to kill gypsy moths reduced spring moth populations by almost 90 percent.(70) In addition, one rare species appeared to have been eradicated from the treatment zone, and moth populations were "heavily impacted in an area more than double that which was actually sprayed" as moths moved into the treatment zone from surrounding areas.(70) In West Virginia, applications of Foray 48B reduced the number of caterpillar species and the number of caterpillars. The year following application, the number of moth species and the number of moths were both reduced.(71) A recent (1994) study in four different Oregon plant communities found that total weight of caterpillars was reduced between 90 and 95 percent by B.t. treatment; the number of caterpillars was reduced by 80 percent; and the number of caterpillar species was reduced by over 60 percent.(72)
Aquatic insects are also affected by B.t. treatments. Canadian studies found that certain stream insects (Simulium vittatum and Taeniopteryx nivalis) were killed by applications of Thuricide and Dipel respectively.(73,74) Midges (chironomids) have repeatedly been shown to be killed by B.t.i.(75-77)
Birds: Because many birds feed on the caterpillars and other insects affected by B.t. applications, it is not surprising that impacts of B.t. spraying on birds have been documented. In Lane County, Oregon studies of chickadees following a gypsy moth spray program found that birds nesting in B.t.- treated areas brought fewer caterpillars to their nests than did birds nesting in untreated areas. The birds were able to find other food, so that nesting success was not significantly impacted.(78) In New Hampshire, when B.t.- treatment reduced caterpillar abundance, black-throated blue warblers made fewer nesting attempts and also brought fewer caterpillars to their nestlings.(79) A Canadian study found that numbers of caterpillars, followed by numbers of two species of warblers and a thrush, were reduced by B.t. treatment. In addition, there were fewer spruce grouse chicks in B.t. treated areas, and the chicks in those areas grew more slowly than chicks in untreated areas.(80)
There is also some evidence that B.t. can be directly toxic to birds. A study of the effects of application of Dipel to ringneck pheasant eggs found that hatching was only half as successful as hatching of untreated eggs. Because the Dipel was applied with a spreader-sticker compound (Plyac) the decrease in hatching may be a result of the Plyac and not the B.t. product.(81)
Other animals: Because shrews often feed on caterpillars, impacts from B.t. treatments are likely. A study in northern Ontario (Canada) found that treatment with Dipel changed the structure of the shrew population. Adult males emigrated, so that the proportion of juveniles increased. The juveniles and adult females who did not emigrate shifted from a diet of caterpillars to alternative prey.(82)
Foray 48B at high concentrations (about 3 percent) is acutely toxic to rainbow trout, probably because the product is highly acidic.(83)
B.t.i. treatments can also affect other animals. Low concentrations of B.t.i. endotoxins decrease the weight of tadpoles and delay their metamorphosis.(84) The B.t.i. formulation Vectobac is acutely toxic to fathead minnows, probably because "inerts" in the product deplete the dissolved oxygen in water.(85) The B.t.i. formulation Teknar was acutely toxic to brook trout fry, probably because of xylene used as an "inert" in the product.(86)
Comparison with synthetic insecticides: Where comparative studies have been done, the ecological impacts of a B.t. treatment are almost always less than those of synthetic insecticides. For example, B.t. treatment of collards caused less of an increase in aphid numbers than did treatment with carbaryl, which killed many aphid predators.(64) Vectobac was much less acutely toxic to an estuary fish than other mosquito insecticides including temephos, fenoxycarb, diflubenzuron, and methoprene.(87)
1. De Barjac, H. and E. Frachon. 1990. Classification of Bacillus thuringiensis strains. Entomophaga. 35(2):233-240.
2. Ellis, R. 1991. BTK. Unpublished report. Winnipeg, MB, Canada: Prairie Pest Management. (January.)
3. Lambert, B. and M. Peferoen. 1992. Insecticidal promise of Bacillus thuringiensis. BioScience 42(2):112-122.
4. Jenkins, J. 1992. Environmental Toxicology and Chemistry Memo. Subject: B.t. Corvallis, OR: Oregon State University Extension Service.
5. Feitelson, J.S., J. Payne and L. Kim. 1992. Bacillus thuringiensis: Insects and beyond. Bio/Technology 10:271-275. (March.)
6. Farm Chemicals Handbook. 1992. Willoughby, OH: Meister Publishing Company.
7. Entwistle, P.F., et al. (eds.) 1993. Bacillus thuringiensis, An environmental biopesticide: Theory and practice. New York: John Wiley & Sons.
8. British Columbia Ministry of Health. 1992. Bacillus thuringiensis. Unpublished report. (December 3.)
9. Gill, S.S., E.A. Cowles and P.V. Pietrantonio. 1992. The mode of action of Bacillus thuringiensis endotoxins. Ann. Rev. Ent. 37:615-636.
10. U.S. EPA. Office of Pesticide Programs. 1990. Pesticide Fact Sheet: Bacillus thuringiensis. Washington, DC. (December.)
11. Novo Nordisk. Enzyme Toxicology Lab. 1990. Bacillus thuringiensis var. kurstaki: Acute oral toxicity/pathogenicity study in rats given B.t.k. tox batch PPQ 2843 (NB 75). Danbury, CT: (July 20.)
12. Berg, N., E.W. Sorensen and J.M. Overholt. 1991. Summary of acute toxicology in support of formula amendment of Foray 48B. Danbury, CT: Novo Nordisk. (May 21.)
13. U.S. EPA. Office of Pesticide Programs. 1994. Tox one- liners. Bacillus thuringiensis Berliner. Washington, D.C. (August 1.)
14. Oshodi, R.O. and R. Macnaughtan. 1990. B.t.k. preparation: Acute inhalation toxicity study in rats. Volume 6. Danbury, CT: Novo Nordisk. (April 20.)
15. Berg, N. 1990. Bacillus thuringiensis var. kurstaki, batch BBB 0073: Acute intravenous toxicity/pathogenicity study in rats. Volume 7. Danbury, CT: Novo Nordisk. (June 19.)
16. Novo Nordisk. Enzyme Toxicology Lab. 1990. Acute dermal toxicity study in rabbits with the end product Foray 48B, batch BBN 6057. Danbury, CT. (December 12.)
17. Siegel, J.P. and J.A. Shadduck. 1988. Mammalian safety of Bacillus thuringiensis israelensis. In de Barjac, H. and D.J. Sutherland. (ed) Bacterial control of mosquitoes & black flies: Biochemistry, genetics & applications of Bacillus thuringiensis israelensis and Bacillus sphaericus. New Brunswick, NJ: Rutgers University Press.
18. Siegel, J.P. and J.A. Shadduck. 1990. Clearance of Bacillus sphaericus and Bacillus thuringiensis ssp. israelensis from mammals. J. Econ. Ent. 83(2):347-355.
19. Thomas, W.E. and D.J.Ellar. 1983. Bacillus thuringiensis var. israelensis crystal delta-endotoxin: Effects on insect and mammalian cells in vitro and in vivo. J. Cell Sci. 60:181-197.
20. Ware, G.W. 1983. Pesticides: Theory and application. New York: W.H. Freeman and Co.
21. Samples, J.R. and H. Buettner. 1983. Ocular infection caused by a biological insecticide. J. Infectious Dis. 148(3):614.
22. Green, M., et al. 1990. Public health implications of the microbial pesticide Bacillus thuringiensis: An epidemiological study, Oregon, 1985-86. Amer. J. Public Health. 80(7):848-852.
23. Noble, M.A., P.D. Riben and G.J. Cook. 1992. Microbiological and epidemiological surveillance program to monitor the health effects of Foray 48B BTK spray. (September 30.) Vancouver, B.C.: Ministry of Forests. Province of British Columbia.
24. Edamura, A., MD. 1992. Affidavit of the Federal Court of Canada, Trial Division. Dale Edwards and Citizens Against Aerial Spraying vs. Her Majesty the Queen, Represented by the Minister of Agriculture. (May 6.)
25. Cameron, D.A., MD. 1992. Letter to Dr. F.J. Blatherwick, Vancouver Medical Health Officer. (March 17.)
26. Washington State Department of Health. 1993. Report of health surveillance activities: Asian gypsy moth control program. Olympia, WA. (March.)
27. Meretoja, T. et al. 1977. Mutagenicity of Bacillus thuringiensis exotoxin. I. Mammalian tests. Hereditus 85:105- 112.
28. Drobniewski, F.A. 1994. A Review: The safety of Bacillus species as insect vector control agents. J. Appl. Bacteriol. 76:101-109.
29. Bennett, R.W. and S.M. Harmon. 1990. Bacillus cereus Food Poisoning. Chapter 8. In Balows, A. et al. (eds.). Laboratory diagnosis of infectious diseases: Principles and practice. Volume 1: Bacterial, mycotic, and parasitic diseases. New York: Springer-Verlag.
30. Martin, K. and L. Baum. 1994. Memorandum to Vicki Skeers, Washington Department of Health, Office of Toxic Substances. Re: Use of Foray 48B in Washington State. (April 18.)
31. Honda, T. et al. 1991. Identity of hemolysins produced by Bacillus thuringiensis and Bacillus cereus. Fed. Europ. Microbiol. Soc. Microbiol. Lett. 79:205-210.
32. Bryant, R.E., J.A. Mazza and L.R. Foster. 1993. Effect of cyclophosphamide-induced neutropenia on susceptibility of mice to lethal infection with Bacillus thuringiensis. Unpublished abstract. Oregon Health Sciences University.
33. Siegel, J.P., J.A. Shadduck and J. Szabo. 1987. Safety of the entomopathogen Bacillus thuringiensis var. israelensis for mammals. J. Econ. Ent. 80:717-723.
34. Oregon Department of Human Resources. Health Division. 1991. Health effects of B.t.: Report of surveillance in Oregon, 1985-87. Precautions to minimize your exposure. Salem, OR: (April 18.)
35. Overholt, Janet. 1992. Telefax to John Bell Re: Potential of Foray 48B to cause allergies. Novo Nordisk. (February 4.)
36. Novo Nordisk. 1991. Material Safety Data Sheet for Foray 48B Flowable Concentrate. Danbury, CT. (February.)
37. Kane, J.C. and D.C. Eaton. 1987. Memorandum Re: Contamination of Dipel 132 with Streptococci bacteria. Abbott Laboratories. (May 15.)
38. Oregon Department of Human Resources. 1992. Letter to Martin Edwards of Novo Nordisk Re: Allergic reaction to a component of Foray 48B. (August 12.)
39. Novo Nordisk. Undated. Foray 48B Inert Ingredients. Danbury, CT.
40. Hutton, P. Product Manager, Insecticide-Rodenticide Branch, Registration Division. U.S. EPA. Date unreadable. Letter to J. Overholt, Novo Nordisk Re: Label Changes for Foray 48B. (February 22.)
41. Bell, J. Asian Gypsy Moth Project Team. Government of Canada. 1992. Memorandum to Mr. Edwards, Asian Gypsy Moth Project Team. Re: Contents of Foray 48B. (February 4.)
42. Harte, J. et al. 1991. Toxics A to Z: A guide to everyday pollution hazards. Berkeley, CA: University of California Press
43. Patnaik, P. 1992. A comprehensive guide to the hazardous properties of chemical substances. New York: Van Nostrand Reinhold .
44. U.S. EPA. Prevention, Pesticides, And Toxic Substances. 1994. Status of Pesticides In Reregistration And Special Review. Washington, D.C. (June.)
45. Fleming, Diana. 1992. Personal communication. (June 29.)
46. Martin, P.A.W. and R.S. Travers. 1989. Worldwide abundance and distribution of Bacillus thuringiensis isolates. Appl. Environ. Microbiol. 55(10):2437-2442.
47. Vaisanen, O.M., J. Mentu, and M.S. Salkinoja-Salonen. 1991. Bacteria in food packaging paper and board. J. Appl. Bacteriol. 71:130-133.
48. West, A.W. and H.D. Burges. 1985. Persistence of Bacillus thuringiensis and Bacillus cereus in soil supplemented with grass or manure. Plant and Soil. 83:389-398.
49. Petras, S.F. and L.E. Casida, Jr. 1985. Survival of Bacillus thuringiensis spores in soil. Appl. Environ. Microbiol. 50:1496-1501.
50. Akiba, Y. 1991. Assessment of rainwater-mediated dispersion of field-sprayed Bacillus thuringiensis in the soil. Appl. Ent. Zool. 26(4):477-483.
51. Reardon, R.C. and K. Haissig. 1984. Efficacy and field persistence of Bacillus thuringiensis after ground application to Balsam fir and white spruce in Wisconsin. Can. Ent. 116:153-158.
52. Huang, Y., R. Huang and K. Li. 1990. A field study of the persisting effect of Bacillus thuringiensis in citrus groves. Chinese J. Biological Control 6(3):131-133.
53. Menon, A.S. and J. De Mestral. 1985. Survival of Bacillus thuringiensis var. kurstaki. Water, Air Soil Pollut. 25:265- 274.
54. Ohana, B., J. Margalit, and Z. Barak. 1987. Fate of Bacillus thuringiensis subsp. israelensis under simulated field conditions. Appl. Environ. Microbiol. 57(4):828-831.
55. Hoti, S.L. and K. Balaraman. 1991. Changes in the populations of Bacillus thuringiensis H-14 and Bacillus sphaericus applied to vector breeding sites. The Environmentalist. 11(1):39-44.
56. Barry, J.W. et al. 1993. Predicting and measuring drift of Bacillus thuringiensis sprays. Environ. Toxicol. Chem. 12:1977-1989.
57. McGaughey, W.M. and M.E. Whalon. 1992. Managing insect resistance to Bacillus thuringiensis toxins. Science 258:1451-1455. (November 27.)
58. McGaughey, W.M. 1990. Insect resistance to Bacillus thuringiensis delta-endotoxin. In Baker, R.R. and P.E. Dunn (eds.) New directions in biological control: Alternatives for suppressing agricultural pests and diseases. New York: Alan R. Liss, Inc. Pp. 583-598.
59. Tabashnik, B.E., N. Finson, and M.W. Johnson. 1991. Managing resistance to Bacillus thuringiensis: Lessons from the diamondback moth (Lepidoptera: Plutellidae). J. Econ. Ent. 84(1):49-55.
60. Rossiter, M., W.G. Yendol, and N.R. Dubois. 1990. Resistance to Bacillus thuringiensis in gypsy moth (Lepidoptera: Lymantriidae): Genetic and environmental causes. J. Econ. Ent. 83(6):2211-2218.
61. Tabashnik, B.E. et al. 1993. Resistance to toxins from Bacillus thuringiensis subsp. kurstaki causes minimal cross- resistance to B. thuringiensis subsp. aizawai in the diamondback moth (Lepidoptera: Plutellidae). Appl. Environ. Microbiol. 59(3): 1332-1335.
62. Gould, F. et al. 1992. Broad-spectrum resistance to Bacillus thuringiensis toxins in Heliothis virescens. Proc. Natl. Acad. Sci. 89:7986-7990.
63. Salama, H.S. et al. 1991. Parasites and predators of the meal moth Plodia interpunctella Hbn. as affected by Bacillus thuringiensis Berl. J. Appl. Ent. 112: 244-253.
64. Horn, D.J. 1983. Selective mortality of parasitoids and predators of Myzus persicae on collards treated with malathion, carbaryl, or Bacillus thuringiensis. Ent. exp. appl. 34: 208-211.
65. Chapman, M.H. and M.A. Hoy. 1991. Relative toxicity of Bacillus thuringiensis var. tenebrionis to the two-spotted spider mite (Tetranychus urticae Koch) and its predator (Metaseiulus occidentalis (Nesbitt)) (Acari, Tetranychidae and Phytoseidae). J. Appl. Ent. 111: 147-154.
66. James, R.R., J.C. Miller, and B. Lighthart. 1993. Bacillus thuringiensis var. kurstaki affects a beneficial insect, the cinnabar moth (Lepidoptera: Arctiidae). J. Econ. Entomol. 86(2): 334-339.
67. Haag, K.H. and G.R. Buckingham. 1991. Effects of herbicides and microbial insecticides on the insects of aquatic plants. J. Aquatic Pl. Manage. 29:55-57.
68. Miller, J.C. 1990. Field assessment of the effects of a microbial pest control agent on nontarget Lepidoptera. Amer. Entomol. (Summer): 135-139.
69. Miller, J.C. 1990. Effects of a microbial insecticide, Bacillus thuringiensis kurstaki, on nontarget Lepidoptera in a spruce budworm-infested forest. J. Res. Lepid. 29(4):267- 276.
70. Crawford, R.L. 1993. Interim one year monitoring of non- target Lepidoptera: Asian gypsy moth aerial spray area, King and Pierce counties, Washington. 30 April Q 13 May 1993. Interim final report in fulfillment of U.S. Dept. of Agriculture Order No. 43-5703-C4286. Seattle, WA: University of Washington, Burke Museum.
71. Sample, B.E. et al. 1993. Evaluation of Bacillus thuringiensis and defoliation effects on native Lepidoptera. AIPM Technology Transfer U.S. Dept. of Agriculture. Forest Service. Northeastern Area. (April.)
72. Savonen, C. 1994. Btk spraying for forest pest kills many other species. OSU News. Corvallis, OR: Oregon State University Agricultural Commnications.
73. Eidt, D.C. 1985. Toxicity of Bacillus thuringiensis var. kurstaki to aquatic insects. Can. Ent. 117:829-837.
74. Kreutzweiser, D.P. et al. 1992. Lethal and sublethal effects of Bacillus thuringiensis var. kurstaki on aquatic insects in laboratory bioassays and outdoor stream channels. Bull. Environ. Contam. Toxicol. 49:252-258.
75. Ali, A. 1981. Bacillus thuringiensis serovar. israelensis (ABG-6108) against chironomids and some nontarget aquatic invertebrates. J. Invert. Pathol. 38:264-272.
76. Molloy, D.P. 1992. Impact of the black fly (Diptera: Simulidae) control agent Bacillus thuringiensis var. israeliensis on chironomids (Diptera: Chironomidae) and other nontarget insects: Results of ten field trials. J. Amer. Mosquito Cont. Assoc. 8(1):24-31.
77. Sinegre, G., B. Gaven, and J.L. Jullien. 1980. Securite d'emploi du serotype H-14 de Bacillus thuringiensis pour la faune non-cible des gites a moustiques du littoral mediterraneen Francais. Parassitologia 22(1,2): 205-211.
78. Gaddis, P.K. and C.C. Corkran. 1986. Secondary effects of BT spray on avian predators: The reproductive success of chestnut-backed chickadees. Portland, OR: Northwest Ecological Research Institute.
79. Rodenhouse, N.L. and R.T. Holmes. 1992. Results of experimental and natural food reductions for breeding black- throated blue warblers. Ecology 73(1):357-372.
80. Bendell, J.F., R.D. James, and B.L. Cadogan. 1990. Effect of B.t.30 var. kurstaki on insects, small birds and mammals, amphibia, and chicks of spruce grouse. Unpublished study. Toronto, Canada: University of Toronto.
81. Jones, I.W. 1986. Summary report: Effect of Dipel( and Plyac( on hatchability of ringneck pheasant eggs. Oregon Dept. of Fish and Wildlife.
82. Bellocq, M.I. et al. 1992. Effects of the insecticide Bacillus thuringiensis on Sorex cinerus (masked shrew) populations, diet, and prey selection in a jack pine plantation in northern Ontario. Can. J. Zool. 70:505-510.
83. Watts, R. (Conservation and Protection Aquatic Toxicity Laboratory, North Vancouver, B.C. Canada). February 20, 1992. Letter to Leslie Schubert, Capilano Salmon Hatchery, Department of Fisheries and Oceans, North Vancouver B.C. Canada. Re: Conduct of fish toxicity tests on Foray 48B.
84. Paulov, S. 1987. Effects of Bacillus thuringiensis (H-14) endotoxins on the development of the frog Rana temporaria L. Acta F.R.N. Univ. Comen. Q Zoologia (30):21-26.
85. Snarski, V.M. 1990. Interactions between Bacillus thuringiensis subsp. israelensis and fathead minnows, Pimephales promelas Rafinesque, under laboratory conditions. Appl. Environ. Microbiol. 56:2618-2622.
86. Fortin, C., D. Lapointe, and G. Charpentier. 1986. Susceptibility of brook trout (Salvelinus fontalis) fry to a liquid formulation of Bacillus thuringiensis serovar. israelensis (Teknar() used for blackfly control. Can. J. Fish Aquat. Sci. 43:1667-1670.
87. Lee, B.M. and G.I. Scott. 1989. Acute toxicity of temephos, fenoxycarb, diflubenzuron, and methoprene and Bacillus thuringiensis var. israelensis to the mummichog (Fundulus heteroclitus). Bull. Environ. Contam. Toxicol. 43:827-832.
Date: 3 Jan 1999 12:15:07 -0600
From: firstname.lastname@example.org (jim mcnulty)
Farmer's Guardian January 1st 99.(UK)
Further work needs to be carried out on the agronomy of Genetically Modified Herbicide Tolerant (GMHT) crops before the possible benefits on biodiversity can understood, according to a new report released by the Minsistry of Agriculture.
The study into the Scientific review of Herbicide use on GM crops claimed the current status of biodiversity was poorly understood, and argued that there had been little independant research to allow an accurate prediction of the potential impacts on wildlife of the introduction of GM crops.
It reported there was, however, no evidence to suggest that either conventional herbicides or those used on GMHT crops would have a direct impact on field margins and and hedgerows adjioning the sprayed fields.
It is to be circulated to interested agricultural and enviromental along with the advisory committee on releases into the enviroment, but critics claimed the report had little of naything new to say.
The survey says that the most likely GMHT crops to be introduced into the UK will be winter and spring oilseed rape, sugar beet, fodder beet and forage maize. which have been modified to become tolerant to the herbicides glyphosate and glufosinate ammonium.
The use of glyphosate and glufosinate in GMHT crops offers the user a simpler programme of sprays that can be applied after the crop emerges, and weed control is likely to be achieved using two or three applications of the herbicides, with slightly better results than spraying with conventional crop techniques.
There is also the oppurtunity to delay weed control in the GMHT crops by a few weeks when compared with current practices, and a possibility that more annual broadleaved weeds would be left in cereals.
And it added that the results of the trials currently taking place involving GMHT crops and and the effect of herbicide on the enviroment should be passed onto the agricultural industry by the Supply Chain Initiative on Modified Agricultural Crops (SCIMAC).
But the Soil Association claimed the report read as if it had been written by the biotech industry and criticised the current policy of allowing the industry to regulate itself over GM Technology.
Patrick Holden, Soil Association director, said the organic sector had to work within a legal framework, face tough certification processes and further independant verification as well as scrutiny by UKROFS to ensure full independance and transparency.
Such widespread scrutiny had to take place when GM crops were being trialled, he insisted, and independant verification was also essential.
Date: 3 Jan 1999 20:28:00 -0600
From: MichaelP email@example.com
By Mark Rowe, INDEPENDENT (London) January 3, 1999
BRITAIN'S largest high street chemist, Boots, has admitted that genetically modified products may be used in some of its own-brand medicines. It has also warned that more products in the future could contain genetically modified components.
Many medicinal products contain ingredients such as thickening agents which are derived from cotton, maize or wheat - plants chosen for genetic modification by big food and chemical companies.
Boots has said it would be "concerned" if it was unable to identify at source whether genetically modified (GM) maize or wheat was being used. It warned that if European suppliers mix up GM and non-GM crops, as happens in the US, then it will become impossible to know whether or not GM elements are present in its products.
Boots admits that may already apply to its own brand of liquid medicines, which use as a thickening agent an acid derived from cellulose, itself derived from cotton made in the US. "Cotton, like maize, can be sourced from the US and as such there is the possibility that a small quantity of a GM crop may sometimes be included," a spokeswoman said.
The announcement comes amid rising public concern at the widespread use of GM wheat, soya and maize in food products before they have been approved for commercial growth in the UK. English Nature, the Government's advisory body on environmental matters, has called for a moratorium on the growth of such crops while trials take place to monitor their effect on the food chain.
Boots' admission has been greeted with dismay by environmental groups such as Friends of the Earth, which is calling for a three-year moratorium on GM food sales until the Government conducts research into the risks. "We would be disappointed in Boots because it is doing it either in ignorance of public concerns or with total contempt," said Adrian Bebb, FoE food campaigner.
Boots, however, said it was sensitive to public worries over GM food. "We're concerned but we probably won't change the formulas for our products next year," said a spokeswoman. "In five years' time nobody is going to be able to give a guarantee over whether the product is GM or not because the US is taking over the market."
Monsanto, the US biotechnology giant, has been marketing GM products worldwide. A secret report for Monsanto, leaked to Greenpeace last month, quoted senior executives from Waitrose, Tesco and Safeway expressing anger at the high-handed way in which, they say, Monsanto brought GM food into Europe by mixing bioengineered soya products with normal ones.
Other concerns centre on starch, which is used for some Boots medical products. Starch is made from maize, which can be genetically modified, along with wheat and soya, to make it resistant to herbicides. Boots said it was certain its brand of paracetamol tablets did not contain GM starch. Boots is testing its food products for GM components and is working closely with suppliers to trace the origin of every ingredient.
Under European Union legislation, the majority of products containing GM ingredients will not be labelled since only those goods that have genetically-altered DNA in their end-product have to be labelled. The exemptions include any food that contains soya oil or soya derivatives such as lecithin. Starch, since it is an additive, does not need to be labelled if it has been genetically modified.
According to FoE, more than 15 per cent of all soya imported from the US is genetically modified and more than 60 per cent of processed foods contain soya. It also believes that up to 95 per cent of all foods that have used GM products in their preparation escape any need for labelling.
Concern has been mounting over the health risks of GM foods. Although GM soya and maize have been approved for safety in the US and Canada, FoE said there had been little independent testing of the implications of eating such foods. "We're concerned that if you cut and splice DNA there's a chance of something going wrong," said Mr Bebb.
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