Current Status of Fall Armyworm Host Strains

1988 ◽  
Vol 71 (3) ◽  
pp. 227 ◽  
Author(s):  
Dorothy P. Pashley
2019 ◽  
Vol 113 (2) ◽  
pp. 800-807
Author(s):  
Kira L Nagoshi ◽  
Sandra A Allan ◽  
Robert L Meagher

Abstract The fall armyworm (Spodoptera frugiperda) (J. E. Smith) (Lepidoptera: Noctuidae), a major agricultural pest in the Western Hemisphere, has recently become established in Africa and Asia. This highly polyphagous species has potential to economically harm multiple crops. Contributing to this host range are two fall armyworm populations historically called ‘host strains’ that differ in host specificity. Understanding behaviors of the two strains is crucial to effective management of this pest. A major difficulty in such studies is that strains have long been considered morphologically indistinguishable, with molecular markers the only reliable means of identification. However, studies of fall armyworm in Colombia reported strain differences in wing morphology sufficiently large to potentially provide a more economical alternative method to determine strain. This study tested whether a similar phenotypic difference was present in Florida populations using geometric morphometric analysis of 15 anatomical landmarks on forewings of 182 specimens from three habitats associated with different host plants. Principle component and linear discriminant analyses identified significant differences in wing size and shape in comparison of strains from different habitats, but not between strains within the same habitat. Data indicate that apparent strain distinctions in wing phenotype are most likely a secondary consequence of differences in developmental growth patterns on different host plants combined with strain-biased host choice. Furthermore, Florida specimens showed much larger phenotypic overlap than observed for strains from Colombia. Together these findings suggest that wing morphology is probably not a reliable indicator of strain identity in field populations where different host plants are available.


2017 ◽  
Vol 110 (6) ◽  
pp. 2568-2575 ◽  
Author(s):  
Rodney N Nagoshi ◽  
Shelby Fleischer ◽  
Robert L Meagher
Keyword(s):  

2011 ◽  
Vol 24 (5) ◽  
pp. 337-347 ◽  
Author(s):  
Robert L. Meagher ◽  
Rodney N. Nagoshi ◽  
Charles J. Stuhl

2020 ◽  
Author(s):  
Katrina A. Schlum ◽  
Kurt Lamour ◽  
Caroline Placidi de Bortoli ◽  
Rahul Banerjee ◽  
Scott J. Emrich ◽  
...  

AbstractThe fall armyworm (Spodoptera frugiperda (J.E. Smith)) is a highly polyphagous agricultural pest with long-distance migratory behavior threatening food security worldwide. This pest has a host range of >80 plant species, but two host strains are recognized based on their association with corn (C-strain) or rice and smaller grasses (R-strain). In this study, the population structure and genetic diversity in 55 S. frugiperda samples from Argentina, Brazil, Kenya, Puerto Rico and the United States (USA) were surveyed to further our understanding of whole genome nuclear diversity. Comparisons at the genomic level suggest panmixia in this population, other than a minor reduction in gene flow between the two overwintering populations in the continental USA that also corresponded to genetically distinct host strains. Two maternal lines were detected from analysis of mitochondrial genomes. We found members from the Eastern Hemisphere interspersed within both continental USA overwintering subpopulations, suggesting multiple individuals were likely introduced to Africa. Comparisons between laboratory-reared and field collected S. frugiperda support similar genomic diversity, validating the experimental use of laboratory strains. Our research is the largest diverse collection of United States S. frugiperda whole genome sequences characterized to date, covering eight continental states and a USA territory (Puerto Rico). The genomic resources presented provide foundational information to understand gene flow at the whole genome level among S. frugiperda populations.


BMC Genomics ◽  
2021 ◽  
Vol 22 (1) ◽  
Author(s):  
Katrina A. Schlum ◽  
Kurt Lamour ◽  
Caroline Placidi de Bortoli ◽  
Rahul Banerjee ◽  
Robert Meagher ◽  
...  

Abstract Background The fall armyworm (Spodoptera frugiperda (J.E. Smith)) is a highly polyphagous agricultural pest with long-distance migratory behavior threatening food security worldwide. This pest has a host range of > 80 plant species, but two host strains are recognized based on their association with corn (C-strain) or rice and smaller grasses (R-strain). The population genomics of the United States (USA) fall armyworm remains poorly characterized to date despite its agricultural threat. Results In this study, the population structure and genetic diversity in 55 S. frugiperda samples from Argentina, Brazil, Kenya, Puerto Rico and USA were surveyed to further our understanding of whole genome nuclear diversity. Comparisons at the genomic level suggest a panmictic S. frugiperda population, with only a minor reduction in gene flow between the two overwintering populations in the continental USA, also corresponding to distinct host strains at the mitochondrial level. Two maternal lines were detected from analysis of mitochondrial genomes. We found members from the Eastern Hemisphere interspersed within both continental USA overwintering subpopulations, suggesting multiple individuals were likely introduced to Africa. Conclusions Our research is the largest diverse collection of United States S. frugiperda whole genome sequences characterized to date, covering eight continental states and a USA territory (Puerto Rico). The genomic resources presented provide foundational information to understand gene flow at the whole genome level among S. frugiperda populations. Based on the genomic similarities found between host strains and laboratory vs. field samples, our findings validate the experimental use of laboratory strains and the host strain differentiation based on mitochondria and sex-linked genetic markers extends to minor genome wide differences with some exceptions showing mixture between host strains is likely occurring in field populations.


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