: a preparation of a bacterium (Bacillus thuringiensis) often modified by genetic engineering for use as a biopesticide against insects and especially lepidopteran larvae
also
: the bacterium itself
baronet
Examples of Bt in a Sentence
Recent Examples on the Web
Lauren Landers, Better Homes & Gardens, 25 June 2025
Mosquito Bits contain the biological pesticide Bt, which kills worms, caterpillars (so be careful with it around pollinator plants) and mosquito larvae.
—Nan Sterman, San Diego Union-Tribune, 5 Apr. 2025
Use Organic Insecticides Bt, insecticidal soap, and neem oil are derived from natural materials and can be used on specific pests.
—Leanne Potts, Better Homes & Gardens, 3 Apr. 2025
The way the toxin gains entry is by activation of Bt’s chitinase which degrades the chitin lining a larva’s digestive tract.
—Joshua Siskin, Orange County Register, 8 Mar. 2025
Finally, if the caterpillar infestation becomes too extensive, Dr. Ghimire recommends Bacillus thuringiensis (Bt), which is a biological control for Lepidoptera species of moths and butterflies.
—Dawn Pettinelli, Hartford Courant, 27 July 2024
That will reduce global emissions by 8.3 Bt CO2, equivalent to 22% of emissions today.
—Wood MacKenzie, Forbes, 28 Feb. 2024
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Noun
For heavy infestations, use an insecticide containing Bt (Bacillus thuringiensis var.
—Lauren Landers, Better Homes & Gardens, 25 June 2025
Mosquito Bits contain the biological pesticide Bt, which kills worms, caterpillars (so be careful with it around pollinator plants) and mosquito larvae.
—Nan Sterman, San Diego Union-Tribune, 5 Apr. 2025
Use Organic Insecticides Bt, insecticidal soap, and neem oil are derived from natural materials and can be used on specific pests.
—Leanne Potts, Better Homes & Gardens, 3 Apr. 2025
The way the toxin gains entry is by activation of Bt’s chitinase which degrades the chitin lining a larva’s digestive tract.
—Joshua Siskin, Orange County Register, 8 Mar. 2025
Finally, if the caterpillar infestation becomes too extensive, Dr. Ghimire recommends Bacillus thuringiensis (Bt), which is a biological control for Lepidoptera species of moths and butterflies.
—Dawn Pettinelli, Hartford Courant, 27 July 2024
That will reduce global emissions by 8.3 Bt CO2, equivalent to 22% of emissions today.
—Wood MacKenzie, Forbes, 28 Feb. 2024
Cite this Entry
“Bt.” Merriam-Webster.com Dictionary, Merriam-Webster, https://www.merriam-webster.com/dictionary/Bt. Accessed 12 Jul. 2025.
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