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ARS Home » Pacific West Area » Maricopa, Arizona » U.S. Arid Land Agricultural Research Center » Pest Management and Biocontrol Research » Research » Publications at this Location » Publication #254844

Title: Fourteen Years of Bt Cotton Advances IPM in Arizona

Author
item Naranjo, Steven
item ELLSWORTH, PETER - University Of Arizona

Submitted to: Southwestern Entomologist
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/20/2010
Publication Date: 9/29/2010
Citation: Naranjo,S.E., Ellsworth,P. 2010. Fourteen years of Bt cotton advances IPM in Arizona. Southwestern Entomologist.35:437-444

Interpretive Summary: The pink bollworm, Pectinophora gossypiella, has been a major pest of cotton in Arizona since the mid 1960’s and has been responsible for tens of millions of dollars of yield loss and control costs annually in the state since that time. A wide range of management tactics have been developed for this pest over the past four decades including cultural methods, mating disruption via pheromones, sterile insect release, insecticides and host plant resistance. Host plant resistance, in the form of transgenic cotton producing the insecticidal protein of Bacillus thuringiensis (Bt cotton) was first commercially grown in 1996 and its adoption and use by growers in Arizona has been rapid. Bt cotton was grown on 86% of the cotton acres by 2006 and as a result of a special exemption by EPA to remove the refuge planting requirement to aid the pink bollworm eradication program, adoption has been over 93% since 2007. Bt cotton provides selective control of pink bollworm and has led to dramatic reductions in pink bollworm populations, and associated crop damage and insecticide use statewide. It has also been a key technology enabling biologically-based control of Bemisia tabaci and Lygus hesperus, two other keys pests of cotton in Arizona. Overall insecticide use in cotton has dropped 88% since 1995. We must remain vigilant to re-invasion of eradicated zones and maintain susceptibility of pink bollworm to Bt cotton to aid continued sustainability of cotton IPM in Arizona.

Technical Abstract: The pink bollworm, Pectinophora gossypiella (Saunders) first invaded Arizona in 1926 and has been a key pest of cotton since the early 1960’s. A broad range of tactics have been developed to manage this pest including a variety of cultural methods, mating disruption via pheromones, sterile insect release and host plant resistance. Transgenic Bt cotton was introduced in 1996 and was rapidly and widely adopted by producers in Arizona. Adoption rose from approximately 57–86% up to 2006 and has been over 93% since 2007 when the state was granted an EPA exemption to eliminate required refuge plantings as part of a regional eradication program. The deployment of Bt cotton for selective control of caterpillars has led to dramatic regional reductions in pink bollworm populations, and associated crop damage and insecticide use. Bt cotton has also been a key technology enabling more selective and biologically-based control approaches for Bemisia tabaci (Gennadius) and Lygus hesperus Knight, two other keys pests of cotton in Arizona. Overall insecticide use (statewide average number of sprays per acre) in cotton has dropped 88% since 1995. Some challenges ahead include re-invasion of eradicated zones, maintaining susceptibility of pink bollworm to Bt cotton, the economics of Bt cotton use in a post-eradication future, and a rapidly changing agroecosystem