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United States Department of Agriculture

Agricultural Research Service

Research Project: EPIDEMIOLOGY AND MANAGEMENT OF XYLELLA FASTIDIOSA (XF) AND OTHER EXOTIC AND INVASIVE DISEASES AND INSECT PESTS

Location: Crop Diseases, Pests and Genetics

Title: Sustained susceptibility of Pink Bollworm to Bt cotton in the United States

Authors
item Tabashnik, Bruce -
item Morin, Shai -
item Unnithan, Gopalan -
item Yelich, Alex -
item Ellers-Kirk, Christa -
item Harpold, Virginia -
item Sisterson, Mark
item Ellsworth, Peter -
item Dennehy, Timothy -
item Antilla, Larry -
item Liesner, Leighton -
item Whitlow, Mike -
item Staten, Robert -
item Fabrick, Jeffrey
item Li, Xianchun -
item Carriere, Yves -

Submitted to: GM Crops
Publication Type: Literature Review
Publication Acceptance Date: April 10, 2012
Publication Date: July 1, 2012
Citation: Tabashnik, B., Morin, S., Unnithan, G., Yelich, A., Ellers-Kirk, C., Harpold, V., Sisterson, M.S., Ellsworth, P., Dennehy, T., Antilla, L., Liesner, L., Whitlow, M., Staten, R., Fabrick, J.A., Li, X., Carriere, Y. 2012. Sustained susceptibility of Pink Bollworm to Bt cotton in the United States. GM Crops. 3:194-200.

Interpretive Summary: Crops genetically engineered to produce insecticidal proteins from the bacterium Bacillus thuringiensis (Bt) kill some key pests and are used extensively worldwide. Benefits of using Bt crops may include reduced insecticide use, regional pest suppression, increased yield, and increased profitability. However, evolution of resistance by target pests threatens to negate these benefits. The pink bollworm is a major cotton pest in many parts of the world and is targeted by transgenic Bt cotton. In China, the frequency of resistance to Cry1Ac has increased, but control failures have not been reported. In western India, pink bollworm resistance to Cry1Ac has caused widespread control failures of Bt cotton. By contrast, in the state of Arizona in the southwestern United States, monitoring data from bioassays and DNA screening demonstrate sustained susceptibility to Cry1Ac for 16 years. Here, factors affecting successful use of Bt cotton against pink bollworm in Arizona are reviewed. From 1996-2005, the main factors that delayed resistance in Arizona appear to be abundant refuges of non-Bt cotton, recessive inheritance of resistance, fitness costs associated with resistance, and incomplete resistance. From 2006-2011, refuge abundance was greatly reduced in Arizona, while mass releases of sterile pink bollworm moths were made to delay resistance as part of a multi-tactic eradication program.

Technical Abstract: Evolution of resistance by pests can reduce the benefits of transgenic crops that produce toxins from Bacillus thuringiensis (Bt) for insect control. One of the world's most important cotton pests, pink bollworm (Pectinophora gossypiella), has been targeted for control by transgenic cotton producing Bt toxin Cry1Ac in several countries for more than a decade. In China, the frequency of resistance to Cry1Ac has increased, but control failures have not been reported. In western India, pink bollworm resistance to Cry1Ac has caused widespread control failures of Bt cotton. By contrast, in the state of Arizona in the southwestern United States, monitoring data from bioassays and DNA screening demonstrate sustained susceptibility to Cry1Ac for 16 years. From 1996-2005, the main factors that delayed resistance in Arizona appear to be abundant refuges of non-Bt cotton, recessive inheritance of resistance, fitness costs associated with resistance, and incomplete resistance. From 2006-2011, refuge abundance was greatly reduced in Arizona, while mass releases of sterile pink bollworm moths were made to delay resistance as part of a multi-tactic eradication program. Sustained susceptibility of pink bollworm to Bt cotton in Arizona has provided a cornerstone for the pink bollworm eradication program and for integrated pest management in cotton. Reduced insecticide use against pink bollworm and other cotton pests has yielded economic benefits for growers, as well as broad environmental and health benefits. We encourage increased efforts to combine Bt crops with other tactics in integrated pest management programs.

Last Modified: 8/22/2014
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