Vol.12_No.2 - Pesticide Alternatives Lab - Michigan State University
Vol.12_No.2 - Pesticide Alternatives Lab - Michigan State University
Vol.12_No.2 - Pesticide Alternatives Lab - Michigan State University
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Spring 2003 Resistant Pest Management Newsletter Vol. 12, <strong>No.2</strong>scientific publications of the 1910s and continuing tothe present, the resistance question has drawnresearchers from fields as diverse as populationgenetics and organic chemistry and in institutionalcontexts ranging from agricultural experiment stationsto industrial research laboratories. To be sure,insecticide resistance research has been primarily thedomain of economic entomology, yet both the ubiquityand complexity of the phenomenon have broughttogether researchers with diverse backgrounds andresearch agendas.Detailing this history is the goal of a new researchproject funded by the Swiss National ScienceFoundation conducted by Christian W. Simon,professor of history at the <strong>University</strong> of Basel, andJohn S. Ceccatti, a post-doctoral research associate onthe project. One of the central questions beingaddressed is how scientists have utilized fieldobservations, laboratory experiments, and theoreticalframeworks to develop explanations of insecticideresistance that were consistent with current biologicalthought. Another area of interest is to compare thevarious research approaches taken by scientists fromvarious disciplines and institutional settings.From the current scientific vantage, the ability ofinsects to develop resistance to insecticides is hardly acontested fact. But even into the 1940s and 1950s, thephenomenon of insecticide resistance continued tochallenge many deeply held convictions amongscientists. For many economic entomologists, forexample, insecticide resistance ran against the longstandingidea of the fixity of biological species innature. Resistance also contradicted a guiding principleof the insecticide industry that once a chemicalcompound was proven effective is would remain soindefinitely. Resistance is also a sticky concept in thegeneral public - and, by extension, those corporatemanagers, policy-makers, and other 'thought leaders'without scientific training. One need only look at ongoingdiscussions (and confusions) about the relatedissue of antibiotic resistance to see that general beliefsin technological 'fixes' to complex problems havestrong staying power.To write the history of insecticide resistanceresearch, the authors draw on a variety of sourcesranging from scientific journals, industry trademagazines, unpublished technical reports fromcompany archives, as well as personal communicationswith scientists currently or formerly involved with theresistance question. On this latter point, the authorswelcome additional input and any interested personscan contact the authors by email atjohn@conceptualresearch.com. A synopsis of theresearch findings will be presented in the next issue ofthe RPM Newsletter.Resistance Management from Around the GlobeBaseline Resistance InformationNative Resistance to Cry1Ac Toxin in Cotton Bollworm, Helicoverpa armigera (Hubner) in South Indian CottonEcosystemGenes from Bacillus thuringiensis coding forcrystal (Cry) toxins of the Cry1A group have beentransferred to and expressed in a number of crops inorder to confer resistance against lepidopteron insectpests (1,2,3). Bt transgenic cotton was cleared by theDepartment of Biotechnology, Government of India forcommercial cultivation for the year 2002, after longdebate and discussion. The primary target pest of thistechnology in India and several other countries is thecotton bollworm, Helicoverpa armigera (Hubner),which causes economic losses up to about Rs. 250billion in India (3,4). Lately, the problems of pestmanagement in cotton and other crops have beencompounded by the development of resistance toinsecticides in H. armigera (5). Outbreaks of H.armigera in south Indian cotton and pigeonpeaecosystems usually lead to severe socio-economicaldisturbances, including several reports of suicide byfarmers. Introduction of insect resistant transgeniccrops, especially Bt transgenics, are expected to be ofimmense value in management and effective control oflepidopteran pests with a significant reduction in theoverall use of insecticides. However, long-termexposure to Bt transgenic crops is likely to renderlepidopteran pests resistant to the Cry toxins due tocontinuous selection pressure (6). Moreover, with theintroduction of transgenic plants, expressing a Crytoxin under the influence of constitutive promoters islikely to hasten this process. The development ofresistance to Bt toxins can be quite distinct, dependingupon the species, selection regime, or geographicalorigin of the founder colony (7). Hence, initial surveysto assess the susceptibility of test insects to the Crytoxins will establish a baseline that can be used inmonitoring resistance development in future. We reportthe resistance of H. armigera to Cry1Ac toxin in 11distinct geographic populations representing the entiresouth Indian cotton ecosystem.10