Bacillus thuringiensis subsp. kurstaki (Btk) is a group of bacteria used as biological control agents against lepidopterans (moths and butterflies). Btk, along with other B. thuringiensis products, is one of the most widely used biological pesticides due to its high specificity; it is effective against lepidopterans, and it has little to no effect on nontarget species. During sporulation, Btk produces a crystal protein that is lethal to lepidopteran larvae.[2] Once ingested by the insect, the dissolution of the crystal allows the protoxin to be released. The toxin is then activated by the insect gut juice, and it begins to break down the gut.[3]
Btk is available commercially and is commonly known as "Garden Dust" or "Caterpillar Killer", both of which are produced by Safer Brand. Other Btk-producing companies include Bonide and Monterey.
Btk is generally regarded as environmentally safe, as its toxicity is essentially limited to its target pest; humans, wildlife, and beneficial insects are regarded as unaffected by the pesticide. Even so, in 2012, a regulatory review of several strains of Bt by the European Food Safety Authority stated that although there was data supporting the claims of low toxicity, the data was insufficient to prove the claims conclusively.[4]
Humansedit
In studies of the effects of Bt on humans, most subjects were unaffected when exposed to Bt. Some individuals reacted with irritation of the eyes and skin. Other subjects with hay fever reported more significant effects, including throat irritation, upset stomach, and difficulty sleeping.
Trichogramma waspsedit
Trichogramma is a genus of parasitoid wasp whose females lay their eggs in the eggs of their hosts; after killing the host, an adult wasp emerges. For this reason, Trichogramma are often used as a biological control agent, and it can even be used in conjunction with pesticides like Btk. In November 2015, a study was conducted examining the effects of Btk on T. chilonis wasps. The study showed that high doses of strains of Btk containing δ-endotoxins were acutely toxic to the wasps, while Btk without these toxins had no adverse effects. It further showed that low doses of Btk, regardless of the strain, led to significantly greater longevity in the wasps.[5]
Soiledit
In a 1998 study, Btk was added to different types of soil in order to determine how the type of soil affected the persistence and concentration of Btk.[6] The results of the study showed that insecticidal activity started to decline after only a month in one soil, while in another toxicity was still high after six months. The authors of the study noted that even though Btk is considered non-toxic to nontarget species, the accumulation and persistence of the Btk toxins could eventually lead to environmental hazards or the selection of Btk-resistant lepidopterans.
Referencesedit
^Bulla LAJ, Davidson LI, Kramer KJ, Jones BL. (1979). "Purification of the insecticidal toxin from the parasporal crystal of Bacillus thuringiensis subsp. kurstaki". Biochem Biophys Res Commun. 91 (3): 1123–1130. doi:10.1016/0006-291x(79)91997-1. PMID 526269.
^Adang, MJ; Staver, MJ; Rocheleau, TA; Leighton, J; Barker, RF; Thompson, DV (1985). "Characterized full-length and truncated plasmid clones of the crystal protein of Bacillus thuringiensis subsp. kurstaki HD-73 and their toxicity to Manduca sexta". Gene. 36 (3): 289–300. doi:10.1016/0378-1119(85)90184-2. PMID 3000881.
^Choma, Christin; Surewicz, Witold; Carey, Paul; Pozsgay, Marianne; Kaplan, Harvey (February 1990). "Secondary structure of the entomocidal toxin from Bacillus thuringiensis subsp. kurstaki HD-73". Journal of Protein Chemistry. 9 (1): 87–94. doi:10.1007/BF01024989. PMID 2340079. S2CID 24749422.
^European Food Safety Authority (2012). "Conclusion on the peer review of the pesticide risk assessment of the active substance Bacillus thuringiensis subsp. kurstaki (strains ABTS 351, PB 54, SA 11, SA 12, EG 2348)". EFSA Journal. 10 (2): 66 pp. doi:10.2903/j.efsa.2012.2540.
Amichot, Marcel; Curty, Christine; Benguettat-Magliano, Olivia; Gallet, Armel; Wajnberg, Eric (February 2016). "Side effects of Bacillus thuringiensis var. kurstaki on the hymenopterous parasitic wasp Trichogramma chilonis". Environmental Science and Pollution Research. 23 (4): 3097–3103. doi:10.1007/s11356-015-5830-7. PMID 26590060. S2CID 19972084.
Amichot, Marcel; Joly, Pierre; Martin-Laurent, Fabrice; Siaussat, David; Lavoir, Anne-Violette (2018-10-10). "Biocontrol, new questions for Ecotoxicology?" (PDF). Environmental Science and Pollution Research. 25 (34 ECOTOX, new questions for terrestrial and aquatic ecotoxicology). European Chemical Society Division of Chemistry and the Environment (Springer): 33895–33900. doi:10.1007/s11356-018-3356-5. ISSN 0944-1344. PMID 30306444. S2CID 52956673. HAL Id: 02051049.
Coll, Moshe; Wajnberg, Eric (25 August 2017). Environmental Pest Management: Challenges for Agronomists, Ecologists, Economists and Policymakers. Hoboken, NJ. pp. xvi+432. doi:10.1002/9781119255574.CH6. ISBN978-1-119-25557-4. OCLC 995357237. S2CID 135321067.{{cite book}}: CS1 maint: location missing publisher (link)ISBN978-1-119-25557-4.: 133
^Tapp, H; Stotzky, G (15 April 1998). "Persistence of the insecticidal toxin from Bacillus thuringiensis subsp. kurstaki in soil". Soil Biology and Biochemistry. 30 (4): 471–476. doi:10.1016/S0038-0717(97)00148-X.
External linksedit
Btk fact sheet
Bt fact sheet
January 01, 1970
bacillus, thuringiensis, kurstaki, bacillus, thuringiensis, subsp, kurstaki, group, bacteria, used, biological, control, agents, against, lepidopterans, moths, butterflies, along, with, other, thuringiensis, products, most, widely, used, biological, pesticides. Bacillus thuringiensis subsp kurstaki Btk is a group of bacteria used as biological control agents against lepidopterans moths and butterflies Btk along with other B thuringiensis products is one of the most widely used biological pesticides due to its high specificity it is effective against lepidopterans and it has little to no effect on nontarget species During sporulation Btk produces a crystal protein that is lethal to lepidopteran larvae 2 Once ingested by the insect the dissolution of the crystal allows the protoxin to be released The toxin is then activated by the insect gut juice and it begins to break down the gut 3 Bacillus thuringiensis kurstaki Scientific classification Domain Bacteria Phylum Bacillota Class Bacilli Order Bacillales Family Bacillaceae Genus Bacillus Species B thuringiensis Subspecies B t kurstaki Trinomial name Bacillus thuringiensis kurstakiBulla et al 1979 1 Btk is available commercially and is commonly known as Garden Dust or Caterpillar Killer both of which are produced by Safer Brand Other Btk producing companies include Bonide and Monterey Contents 1 Effects on nontarget species 1 1 Humans 1 2 Trichogramma wasps 1 3 Soil 2 References 3 External linksEffects on nontarget species editBtk is generally regarded as environmentally safe as its toxicity is essentially limited to its target pest humans wildlife and beneficial insects are regarded as unaffected by the pesticide Even so in 2012 a regulatory review of several strains of Bt by the European Food Safety Authority stated that although there was data supporting the claims of low toxicity the data was insufficient to prove the claims conclusively 4 Humans edit In studies of the effects of Bt on humans most subjects were unaffected when exposed to Bt Some individuals reacted with irritation of the eyes and skin Other subjects with hay fever reported more significant effects including throat irritation upset stomach and difficulty sleeping Trichogramma wasps edit Trichogramma is a genus of parasitoid wasp whose females lay their eggs in the eggs of their hosts after killing the host an adult wasp emerges For this reason Trichogramma are often used as a biological control agent and it can even be used in conjunction with pesticides like Btk In November 2015 a study was conducted examining the effects of Btk on T chilonis wasps The study showed that high doses of strains of Btk containing d endotoxins were acutely toxic to the wasps while Btk without these toxins had no adverse effects It further showed that low doses of Btk regardless of the strain led to significantly greater longevity in the wasps 5 Soil edit In a 1998 study Btk was added to different types of soil in order to determine how the type of soil affected the persistence and concentration of Btk 6 The results of the study showed that insecticidal activity started to decline after only a month in one soil while in another toxicity was still high after six months The authors of the study noted that even though Btk is considered non toxic to nontarget species the accumulation and persistence of the Btk toxins could eventually lead to environmental hazards or the selection of Btk resistant lepidopterans References edit Bulla LAJ Davidson LI Kramer KJ Jones BL 1979 Purification of the insecticidal toxin from the parasporal crystal of Bacillus thuringiensis subsp kurstaki Biochem Biophys Res Commun 91 3 1123 1130 doi 10 1016 0006 291x 79 91997 1 PMID 526269 Adang MJ Staver MJ Rocheleau TA Leighton J Barker RF Thompson DV 1985 Characterized full length and truncated plasmid clones of the crystal protein of Bacillus thuringiensis subsp kurstaki HD 73 and their toxicity to Manduca sexta Gene 36 3 289 300 doi 10 1016 0378 1119 85 90184 2 PMID 3000881 Choma Christin Surewicz Witold Carey Paul Pozsgay Marianne Kaplan Harvey February 1990 Secondary structure of the entomocidal toxin from Bacillus thuringiensis subsp kurstaki HD 73 Journal of Protein Chemistry 9 1 87 94 doi 10 1007 BF01024989 PMID 2340079 S2CID 24749422 European Food Safety Authority 2012 Conclusion on the peer review of the pesticide risk assessment of the active substance Bacillus thuringiensis subsp kurstaki strains ABTS 351 PB 54 SA 11 SA 12 EG 2348 EFSA Journal 10 2 66 pp doi 10 2903 j efsa 2012 2540 Amichot Marcel Curty Christine Benguettat Magliano Olivia Gallet Armel Wajnberg Eric February 2016 Side effects of Bacillus thuringiensis var kurstaki on the hymenopterous parasitic wasp Trichogramma chilonis Environmental Science and Pollution Research 23 4 3097 3103 doi 10 1007 s11356 015 5830 7 PMID 26590060 S2CID 19972084 Amichot Marcel Joly Pierre Martin Laurent Fabrice Siaussat David Lavoir Anne Violette 2018 10 10 Biocontrol new questions for Ecotoxicology PDF Environmental Science and Pollution Research 25 34 ECOTOX new questions for terrestrial and aquatic ecotoxicology European Chemical Society Division of Chemistry and the Environment Springer 33895 33900 doi 10 1007 s11356 018 3356 5 ISSN 0944 1344 PMID 30306444 S2CID 52956673 HAL Id 02051049 Coll Moshe Wajnberg Eric 25 August 2017 Environmental Pest Management Challenges for Agronomists Ecologists Economists and Policymakers Hoboken NJ pp xvi 432 doi 10 1002 9781119255574 CH6 ISBN 978 1 119 25557 4 OCLC 995357237 S2CID 135321067 a href Template Cite book html title Template Cite book cite book a CS1 maint location missing publisher link ISBN 978 1 119 25557 4 133 Tapp H Stotzky G 15 April 1998 Persistence of the insecticidal toxin from Bacillus thuringiensis subsp kurstaki in soil Soil Biology and Biochemistry 30 4 471 476 doi 10 1016 S0038 0717 97 00148 X External links editBtk fact sheet Bt fact sheet Retrieved from https en wikipedia org w index php title Bacillus thuringiensis kurstaki amp oldid 1155757995, wikipedia, wiki, book, books, library,
