Author
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Westbrook, John |
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Lopez, Juan De Dios |
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Submitted to: Southwestern Entomologist
Publication Type: Peer Reviewed Journal Publication Acceptance Date: 7/20/2010 Publication Date: 9/29/2010 Citation: Westbrook, J.K., Lopez, J. 2010. Long distance migration in Helicoverpa zea: What we know and need to know. Southwestern Entomologist. 35:355-360. Interpretive Summary: The corn earworm is a significant pest of corn, cotton and several other field crops in the U.S., and crop protection tactics are available to control corn earworm larvae that have infested the plants. However, information is lacking to accurately predict migratory flights of corn earworm moths and develop tactics that proactively reduce their capability to infest large cropping regions such as the northern tier of states where extensive insecticide applications are made for control of immigrant corn earworms in sweet corn, seed corn, snap beans and other high-value crops. We emphasize three critical elements that affect the timing and extent of corn earworm migration: period of adult corn earworm emergence, availability of fruiting corn as a host, and availability of suitable atmospheric conditions for transport. Technologies to predict and control corn earworm migration is particularly important to the abundance, geographic range, and management of corn earworm populations relative to potential climate change and use of transgenic crops tolerant of drought and heat conditions. Technical Abstract: This paper identifies knowledge and knowledge gaps in the areas of biology and ecology, and migratory flight of corn earworm, Helicoverpa zea (Boddie). The paper focuses on results from studies of H. zea population dynamics and migration in Texas during a period of substantial irrigated corn production in the Lower Rio Grande Valley, which prevailed before planted acres decreased due to drought, expansive land development, and the introduction of Bt corn. Because overwintering survival of H. zea in the U.S. is generally accepted to be limited to areas south of 40 degrees north latitude, much of the corn-growing area in the north-central U.S. would not be infested by H. zea if not for migration. Overwintering emergence contributes to infestations of H. zea, but it is very difficult to separate the contributions of overwintering emergence and immigrants on local populations. We emphasize three critical elements affecting the timing and extent of H. zea migration: period of adult H. zea emergence, availability of fruiting corn as a host, and availability of suitable atmospheric conditions for transport. Knowledge of H. zea migration will be especially useful in devising and utilizing novel control tactics in the northern tier of states where extensive insecticide applications are made for control of immigrant H. zea in sweet corn, seed corn, snap beans and other high-value crops. This is particularly important to the abundance, geographic range, and management of H. zea populations relative to potential climate change and use of transgenic crops tolerant of drought and heat conditions. |
