BIOLOGICALLY-BASED TECHNOLOGIES FOR MANAGEMENT OF CROP INSECT PESTS IN LOCAL AND AREAWIDE PROGRAMS
Location: Insect Behavior and Biocontrol Research Unit
Title: Inferring the annual migration patterns of fall armyworm (Lepidoptera: Noctuidae) in the U.S. from mitochondrial haplotypes.
Submitted to: Ecology and Evolution
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: March 31, 2012
Publication Date: July 1, 2012
Citation: Nagoshi, R.N., Meagher Jr, R.L., Hay-Roe, M.M. 2012. Inferring the annual migration patterns of fall armyworm (Lepidoptera: Noctuidae) in the U.S. from mitochondrial haplotypes. Ecology and Evolution. 2(7):1458-1467.
Interpretive Summary: Annual long distance migration is used by many species to extend their geographical range into areas that cannot support permanent populations. A classic example is the fall armyworm, a semi-tropical moth that is not known to survive freezing winters. Yet fall armyworm infestations occur throughout the central and eastern United States during the spring-fall agricultural season, extending as far north as Canada. These derive from migratory populations that originate from two overwintering regions, southern Florida or southern Texas-Mexico, where winters are mild and host plants are available. Scientists at the USDA-Agriculture Research Service,Center for Medical Agricultural and Veterinary Entomology, Gainesville, Florida, are describing the pattern of these movements in order to predict the timing and severity of infestations. In addition, invasive species and strains represent a continuing threat to U.S. agriculture. Migratory insects are of particular concern because their high mobility facilitates both entry and subsequent spread into new geographical areas. Many of these potential pests are tropical in origin and so are likely to become established in the same regions where fall armyworm overwinters. As such, their dispersion pattern is likely to be similar.
Spodoptera frugiperda (J.E. Smith) or fall armyworm is an important agricultural pest of a number of crops in the Western Hemisphere. In the U.S., infestations in corn acreages extend from the Mexican to the Canadian border. Because fall armyworm does not survive prolonged ground freezing the infestations annually affecting most of North America are migrants from southern Texas and Florida where winter temperatures are mild and host plants available. A novel haplotype method was developed that can distinguish between these two geographically distant overwintering populations, with the potential to delineate the associated migratory pathways. Several years of collections from major corn producing areas in the southern, central, and eastern U.S were used to map the geographical distribution of the fall armyworm haplotypes. From these haplotype profiles it was possible to develop the most detailed description yet of the annual northward movements of fall armyworm. The consistency of these results with past studies and the implications on our understanding of fall armyworm biology are discussed. A better understanding of fall armyworm populations and their movement is critical for the development of strategies to predict infestation levels and eventually control this pest in the United States.