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United States Department of Agriculture

Agricultural Research Service

Research Project: BIOLOGICALLY-BASED TECHNOLOGIES FOR MANAGEMENT OF CROP INSECT PESTS IN LOCAL AND AREA-WIDE PROGRAMS Title: Identification and comparison of fall armyworm (Lepidoptera:Noctuidae) host strains in Brazil, Texas, and Florida

Authors
item Nagoshi, Rodney
item Silvie, Pierre - CIRAD-MONTPELLIER, BRAZIL
item Meagher, Robert
item Lopez, Juan - USDA, COLLEGE STATION,TX
item Machado, Vilmar - UNISINOS, BRAZIL

Submitted to: Annals of the Entomological Society of America
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: November 20, 2006
Publication Date: May 1, 2007
Citation: Nagoshi, R.N., Silvie, P., Meagher Jr, R.L., Lopez, J., Machado, V. 2007. Identification and comparison of fall armyworm (Lepidoptera: Noctuidae) host strains in Brazil, Texas, and Florida. Annals of the Entomological Society of America. 100(3):394-402.

Interpretive Summary: Spodoptera frugiperda (J.E. Smith; Lepidoptera: Noctuidae) or fall armyworm is an important agricultural pest of a number of crops in the western hemisphere. Two identical host strains of fall armyworm exist that differ in plant host usage and habitat distribution. The corn (C) strain is the primary pest of corn, while the rice (R) strain is the majority population infesting rice and turf grass. While there is evidence of different strains in Brazil, it has not been demonstrated that these are equivalent to the United States strains. Scientists at the Center for Medical, Agricultural, and Veterinary Entomology in Gainesville, Florida tested this by examining Brazilian fall armyworm populations for genetic markers diagnostic of strains present in Florida and Texas and determining whether they displayed the expected biases in plant host distributions. The genetic analysis demonstrated that the fall armyworm in Brazil are nearly identical to those found in the two major U.S. populations that overwinter in Texas and Florida. The two Brazilian strains displayed biases in plant host distribution similar to that observed in the U.S. These results indicate that the biology and behaviors of fall armyworm demonstrated from studies of North American specimens are applicable to populations in Brazil.

Technical Abstract: Fall armyworm is a major economic pest throughout the western hemisphere. Studies of populations in the southern United States and the Caribbean demonstrated the existence of two morphologically identical but genetically distinct host strains. Fall armyworm populations in Brazil are geographically distant from those of North America and are probably reproductively isolated. While there is evidence of different biotypes in Brazil, it has not been demonstrated that these are equivalent to the United States strains. We tested this by examining Brazilian fall armyworm populations for genetic markers diagnostic of strains present in Florida and Texas and determining whether they displayed the expected biases in plant host distributions. Polymorphisms in the mitochondrial Cytochrome Oxidase I gene define two distinct maternal lineages that correlate with strain-specific behaviors in Florida populations. The same two mitochondrial haplotypes exist in Brazil and were nearly identical to those found in the two major U.S. populations that overwinter in Texas and Florida. The two Brazilian haplotypes displayed biases in plant host distribution similar to that observed in the U.S. These results indicate that the biology and behaviors of Brazilian fall armyworm populations are similar to those found in North America.

Last Modified: 10/22/2014
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