Journal ArticleDOI
Some Factors Affecting the Pathogenicity of Bacillus thuringiensis Berliner Against Blackflies
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Several factors that might affect the efficacy of Bacillus thuringiensis against Simulium vittatum larvae were investigated in the laboratory utilizing a conical-flushing rearing unit and the jar method for bioassay.Abstract:
Several factors that might affect the efficacy of Bacillus thuringiensis against Simulium vittatum larvae were investigated in the laboratory utilizing a conical-flushing rearing unit and the jar method for bioassay.
S. vittatum and S. argus were considerably more susceptible to B. thuringiensis than the other species tested. There was a strong positive correlation between temperature and mortality (r = 0.97). The range of mortality for 4°–24°C was 23–95%. The midgut pH ranged from 8.2–11.4, sufficiently high for θ-endotoxin activity.
When spore and crystal fractions were bioassayed separately, only the crystal fraction produced significant mortality. No additive action of the spore and crystal was apparent, activity was solely attributed to the parasporal crystalline inclusion bodies. Spore preparations autoclaved and not autoclaved, containing the β -exotoxin produced a low level of mortality at 10 ppm for 24 h.
Spore suspensions of B. thuringiensis stored at 2° and 19°C remained active for 167 and 28 days, respectively, after which a sharp decline in activity was observed.read more
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Journal ArticleDOI
Invitation paper (c.p. alexander fund): history of bacillus thuringiensis berliner research and development
TL;DR: This review article starts with the discovery of Bacillus thuringiensis Berliner in Japan at the turn of the century and notes that the observations of the early Japanese workers clearly show that they were aware of the toxin-mediated nature of the activity of B .
Book ChapterDOI
Formulation of Bacteria, Viruses and Protozoa to Control Insects
H. Denis Burges,K. A. Jones +1 more
TL;DR: Three major groups of insect pathogens - bacteria, viruses and Protozoa - have one feature in common: they normally infect or poison the insects perorally when they contaminate insect food, so formulation must replace the natural protection afforded by insect cadavers.
Journal ArticleDOI
Pathogenesis and midgut histopathology of Bacillus thuringiensis in Simulium vittatum (Diptera: Simuliidae)
TL;DR: The pathogenesis and midgut histopathology which resulted when larvae of the blackfly were exposed to Bacillus thuringiensis at various temperatures and periods of exposure were investigated, with gross signs of disease included cessation of feeding and tetany with brachytosis.
Journal ArticleDOI
Control of insects by bacteria
TL;DR: All bacteria in microbial insecticides are species of Bacillus and form spores since they have to survive in the environment and on the shelf, although bacteria are not likely to supplant chemical insecticides on a large scale in the near future.
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