Current status of insecticide resistance in Q biotype Bemisia tabaci populations from Crete |
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| Authors: | Emmanouil Roditakis Maria Grispou Evangelia Morou Jon Bent Kristoffersen Nikos Roditakis Ralf Nauen John Vontas Anastasia Tsagkarakou |
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| Institution: | 1. National Agricultural Research Foundation, Plant Protection Institute of Heraklion, PO Box 2228, 71003 Heraklion, Greece;2. Laboratory of Pesticide Science, Agricultural University of Athens, Iera Odos 75, Athens 11855, Greece;3. Vector Research, Liverpool School of Tropical Medicine, Pembroke Place Liverpool L3 5QA, UK;4. Research Insecticides, Bayer AG, Agrochemicals Division, D‐40789 Monheim, Germany |
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| Abstract: | BACKGROUND: A major problem of crop protection in Crete, Greece, is the control of Bemisia tabaci (Gennadius) (Homoptera: Aleyrodidae) with chemical insecticides owing to the rapid development of resistance. The aim of this study was to investigate the establishment of resistance and the underlying mechanisms to major insecticide classes with classical bioassays and known biochemical resistance markers. RESULTS: During a 2005–2007 survey, 53 Q biotype populations were collected. Application history records showed extensive use of neonicotinoids, organophosphates, carbamates and pyrethroids. High resistance levels were identified in the majority of populations (>80%) for imidacloprid (RF: 38–1958×) and α‐cypermethrin (RF: 30–600×). Low resistance levels (RF < 12) were observed for pirimiphos‐methyl. A strong correlation between resistance to imidacloprid and the number of applications with neonicotinoids was observed. Significant correlations were observed between COE and P450‐dependent monoxygenase activity with resistance to α‐cypermethrin and imidacloprid respectively. A propoxur‐based AChE diagnostic test indicated that iAChE was widespread in most populations. Resistance levels for α‐cypermethrin were increased when compared with a previous survey (2002–2003). Differentiation of LC50 values between localities was observed for imidacloprid only. CONCLUSION: Bemisia tabaci resistance evolved differently in each of the three insecticides studied. Imidacloprid resistance seems less established and less persistent than α‐cypermethrin resistance. The low resistance levels for pirimiphos‐methyl suggest absence of cross‐resistance with other organophosphates or carbamates used. Copyright © 2008 Society of Chemical Industry |
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| Keywords: | insecticide resistance Bemisia tabaci Q biotype imidacloprid α ‐cypermethrin pirimiphos methyl Crete |
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