Bacillus thuringiensis
Summary
What it is
Common uses
Public Perception
Anxiety level
Cultural claims
Source sentiment
History
Timeline
Origin
Science
Key findings
Studies
Safety status
Nuance
Alternatives
Swaps
Avoidance tips
References

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Bacillus thuringiensis

ingredientPesticides

Total Sources: 43

Verified Claims: 33

Scientific Sources: 19

Also known as: Bt

Summary

Bacillus thuringiensis (Bt) is a soil-dwelling bacterium that produces proteins toxic to certain insects and is used as a bioinsecticide in agriculture and pest control [12], [3], [22]. It is also incorporated into genetically modified crops [12], [20].

What it is

Bacillus thuringiensis (Bt) is a Gram-positive, spore-forming bacterium found in soil [13], [15]. It produces crystal proteins (Cry toxins) during sporulation that have insecticidal properties [3], [13].

Common uses

  • Insecticide sprays for agriculture and organic farming [22], [23]

  • Genetic modification of crops to produce insecticidal toxins [12], [20]

  • Mosquito and black fly control [25]

Public Perception

Anxiety level

Moderate. Concerns exist regarding potential allergenicity, impact on non-target organisms, and the development of resistance in insect populations [3], [12], [13].

Cultural claims

  • GMO crops are unsafe and ineffective [20]

  • Bt is a safe and effective tool for pest control [12]

Source sentiment

Mixed. Some sources express concern over potential health and environmental impacts, while others emphasize its safety and benefits as a biopesticide [3], [12], [13], [20].

History

Timeline

1911

Ernst Berliner isolated Bacillus thuringiensis from a Mediterranean flour moth [14].

1920

Farmers began using Bt as a pesticide [14].

1938

France started producing commercial spore-based formulations called Sporine [14].

1956

Researchers discovered that the parasporal crystal is responsible for insecticidal activity [14].

1958

Commercial use of Bt began in the US [14].

1961

Bt was registered as a pesticide with the EPA [14].

1995

The first genetically engineered Bt corn was registered with the EPA [14].

Origin

Identified as the cause of sotto disease in silkworms [14].

First appeared: 1901

Science

Key findings

  • Bt Cry proteins used in genetically modified crops do not negatively affect the survival of honey bee larvae or adults in laboratory settings [5].

  • Bt maize does not have significant effects on non-target arthropod taxa in the field in southern Europe [6].

  • Bt toxins can alter bacterial communities and their potential functions in earthworm intestines, but these effects may not be persistent [13].

Studies

An overview of the safety and biological effects of Bacillus thuringiensis Cry toxins in mammals

While 'toxic' is not appropriate for defining the effects these toxins have on mammals, they cannot be considered innocuous, as they have some physiological effects that may become pathological [3].

A Meta-Analysis of Effects of Bt Crops on Honey Bees

Bt Cry proteins used in genetically modified crops commercialized for control of lepidopteran and coleopteran pests do not negatively affect the survival of either honey bee larvae or adults in laboratory settings [5].

Bt toxins alter bacterial communities and their potential functions in earthworm intestines

Earthworm intestinal microbial communities confer strong resilience and the ability to adapt to Bt toxin stress, with no persistent adverse effects observed after earthworm exposure to Bt toxins [13].

Safety status

Generally regarded as safe for mammals, but some studies suggest potential physiological effects [3].

Nuance

The specificity of Cry toxins depends on factors such as pH, digestive enzymes in the host insect gut, and the presence of specific host receptors [25].

Alternatives

Other natural insect repellents

To avoid potential exposure to Bt toxins, consider using alternative natural insect repellents [27].

Where to find: MedicalNewsToday.com lists several natural insect repellents [27].

Organic produce

To minimize pesticide exposure, choose certified organic produce [31], [37].

Where to find: Organic produce can be found at most grocery stores and farmers' markets [37].

Avoidance tips

  • Wash produce thoroughly under cold running water [37].

  • Peel fruits and vegetables when appropriate to remove surface residues [37].

References

1.

https://www.efsa.europa.eu/sites/default/files/2025-08/EFSA%20Journal%20-%202025%20-%20%20-%20Current%20practice%20%20challenges%20and%20future%20opportunities%20in%20the%20safety%20assessment%20of%20newly%20expressed.pdf