Role of transgenic Bt-crops in promoting biological control and integrated pest management


  • Bio-Control Research Laboratories, Pest Control India Ltd., Monsanto Research Centre, Former Vice President, Bengaluru, Karnataka, 560092, India


Since their commercial introduction in 1996 in the USA, the insect resistant transgenic Bt crops, notably Bt-cotton and Bt-corn, have given effective control of target pests and found overwhelming adoption in several countries. As of 2017, these Bt crops were cultivated in 14 countries on 100 m ha, including 11.4 m ha of Bt-cotton in India, which comprised 53% of 189.8 m ha of all GM crops grown in 24 countries. Such extensive cultivation of Bt crops, incorporated with genes derived from the soil bacterium, Bacillus thuringiensis (Bt), modified to express host-specific insecticidal crystalline (Cry) proteins, has resulted in higher crop yields by 22%, increased farmers’ profit by 68% and reduced chemical insecticide applications by 37%, thereby providing social, economic, health and environmental benefits. The reduced chemical sprays have contributed to conservation of parasitoids and predators leading to enhanced biological control in crop systems. Feeding tests carried out with predators like ladybird beetles and green lacewing and also with hymenopteran parasitoids have demonstrated Bt proteins to be safe to these natural enemies. The value of Bt crops in promoting biological control and integrated pest management is discussed.


Bt-cotton, Bt-corn, biosafety, IPM, parasitoids, predators

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Al-Deeb MA, Wilde GE, Higgins RA. 2001. No effect of Bacillus thuringiensis on the predator Orius insidiosus (Hemiptera: Anthocoridae). Environ Entomol. 30: 625629.

Barwale RB, Gadwal VR, Zehrm U, Zehr B. 2004. Prospects for Bt cotton technology in India. Ag Bio Forum. 7: 23-26.

Bernal JS, Griset JG, Gillogly PO. 2002. Impacts of developing on Bt maize-intoxicated hosts on fitness parameters of a stem borer parasitoid. J Ent Sci. 37: 27-40.

Betz FS, Hammond BG, Fuchs RL. 2000. Safety and advantages of Bacillus thurigiensis-protected plants to control insect pests. Regulatory Toxicology and Pharmacology. 32: 156-173. PMid:11067772

Candolfi M, Brown K, Reber B, Schmidli H. 2004. A faunistic approach to assess potential side-effects of genetically modified Bt-corn on non-target arthropods under field conditions. Biocontrol Sci Technol. 14: 129-170.

Dutton A, Klein H, Romeis J, Bigler F. 2002. Uptake of Bt-toxin by herbivores on transgenic maize and consequences for the predator Chrysoperla carnea. Ecol Ent. 27: 441-447.

English L, Slatin SL. 1992. Mode of action of delta-endotoxin from Bacillus thuringiensis: a comparison with other bacterial toxins. Insect Biochem Mol Biol. 22: 1-7.

Entine J. 2013. Are GMOs safe? Global Independent Science OrganizationsWeigh-in. Available from:

EPA. 2001. Biopesticides Registration Action Document (BRAD) Bacillus thuringiensis Plant-Incorporated Protectants. October 2001.

Hagerty AM, Kilpatrick AL, Turnipseed SG, Sullivan MJ, Bridges WC. 2005. Predaceous arthropods and lepidopteran pests on conventional, Bollgard and Bollgard II cotton under untreated and disrupted conditions. Environ Entomol. 34: 105-114.

Head G. 2005. Assessing the influence of Bt crops on natural enemies. Second International Symposium on Biological Control of Arthropods. Davos, Switzerland, Sept. 12-16, 2005: 346-355. PMid:15772652

Head GP, Brown CR, Groth ME, Duan JJ. 2001. Cry1Ab protein levels in phytophagous insects feeding on transgenic corn: implications for secondary exposure risk assessment. Entomol Exp et Appl. 99: 37-45.

Hilbeck A, Moar WJ, Pusztai-Carey M, Filippini A, Bigler F. 1998a. Toxicity of Bacillus thuringiensis Cry1Ab toxin to the predator Chrysoperla carnea (Neuroptera: Chrysopidae). Environ Entomol. 27: 1255-1263.

Hilbeck A, Baumgartner M, Fried PM, Bigler F. 1998b. Effects of transgenic Bacillus thuringiensis corn-fed prey on mortality and development time of immature Chrysoperla carnea (Neuroptera: Chrysopidae).

Environ Entomol. 27: 480-487 ee/27.2.480

Hilbeck A, Moar WJ, Pusztai-Carey M, Filippini A, Bigler F. 1999. Prey-mediated effects of Cry1Ab toxin and protoxin and Cry2A protoxin on the predator Chrysoperla carnea. Entomol Exp et Appl. 91: 305-316.

ICGEB (International Centre for Genetic Engineering and Biotechnology). Biosafety Databases. Available from

IGMORIS (Indian GMO Research Information System). 2013. Biosafety data of approved Genes/Events of GM cotton. Available from: developments1.asp

ISAAA. 2017. Global Status of Commercialized Biotech/ GM Crops in 2017: Biotech Crop Adoption Surges as Economic Benefits Accumulate in 22 Years. ISAAA Brief No. 53. ISAAA: Ithaca, NY.

Jun-Ce Tian, Ju Yao, Li-Ping Long, Romeis J, Shelton AM. 2015. Bt crops benefit natural enemies to control non-target pests. Sci Rep. 5: 16636. PMid:26559133 PMCid:PMC4642322

Lozzia GC. 1999. Biodiversity and structure of ground beetle assemblages (Coleoptera: Carabidae) in Bt corn and its effects on non target insects. Bollettino Zool Agraria Bachicoltura. 31: 37-58.

Manjunath TM. 2005. A Decade of Commercialized Transgenic Crops – Analyses of Their Global Adoption, Safety and Benefits. The Sixth Dr. S. Pradhan Memorial Lecture, Indian Agricultural Research Institute (IARI), New Delhi, 23 March 2005. Available from:

Manjunath TM. 2011. Q & A on Bt-cotton in India:Answers to more than 85 questions. Second Edition (First Edition, 2007). Association of Biotechnology Led Enterprises – Agricultural Group (ABLE-AG), Bengaluru, 112 p. Available from:

Manjunath TM, Mohan KS. 2015. GM Crops: Perception vs reality. Association of Biotechnology Led Enterprises - Agricultural Group, Bengaluru, Karnataka (India), 28+10 pages

McClintock JT, Schaffer CR, Sjoblad RD. 1995. A comparative review of the mammalian toxicity of Bacillus thuringiensis-based pesticides. Pesti Sci. 45: 95-105.

Perlak FJ, Deaton RW, Armstrong TA, Fuchs RL, Sims SS, Greenplate JT, Fischhoff DA. 1990. Insect resistant cotton plants. BioTechnology. 8: 939-943. PMid:1366777

Perlak FJ, Fuchs R., Dean DA, McPherson SL, Fischhoff DA. 1991. Modification of the coding sequence enhances plant expression of insect cotton protein genes. Proc Nat Acad Sciences. 88: 3324-3328. pnas.88.8.3324 PMid:2014252

Pilcher CD, Obrycki JJ, Rice ME, Lewis LC. 1997. Preimaginal development, survival and field abundance

of insect predators on transgenic Bacillus thuringiensis corn. Environ Entomol. 26: 446-454.

Raps A, Kehr J, Gugerli P, Moar WJ, Bigler F, Hilbeck A. 2001. Immunological analysis of phloem sap of Bacillus thuringiensis corn and of the non-target herbivore Rhopalosiphum padi (Homoptera: Aphididae) for the presence of Cry1Ab. Mol Ecol. 10: 525-533. PMid:11298965

Romeis J, Dutton A, Bigler F. 2004. Bacillus thuringiensis toxin (Cry1Ab) has no direct effect on larvae of the green lacewing Chrysoperla carnea (Stephens) (Neuroptera: Chrysopidae). J Insect Physiol. 50: 175-183. PMid:15019519

Sanahuja G, Banakar R, Twyman RM, Capell T, Christou, P. 2011. Bacillus thuringiensis: a century of research, development and commercial applications. Pl Biotechnol J. 9: 283-300. j.1467-7652.2011.00595.x PMid:21375687

Wendel J, 2013. With 2000+ global studies affirming safety, GM foods among most analysed in science. Genetic Literacy Project, Oct 8, 2013. Available from:

WHO, 1999.Microbial pest control agent, Bacillus thuringiensis. Environmental Health Criteria 127.World Health Organization, Geneva, 125 PP.

Wu KM, GuoYY. 2005. The evolution of cotton pest management practices in China. Annu Rev Entomol. 50: 31-52. PMid:15355239

Xia J. Y, Cui-Jin J, Ma LH, Dong SL, Cui, XF. 1999. The role of transgenic Bt cotton in integrated insect pest management. Acta Gossypii Sinica. 11: 57-64.


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