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Robert L Meagher - One of the best experts on this subject based on the ideXlab platform.
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A computational model to predict the population dynamics of Spodoptera frugiperda
Journal of Pest Science, 2019Co-Authors: Adriano G. Garcia, Cláudia P. Ferreira, Wesley A. C. Godoy, Robert L MeagherAbstract:Among lepidopteran insects, the fall Armyworm, Spodoptera frugiperda , deserves special attention because of its agricultural importance. Different computational approaches have been proposed to clarify the dynamics of fall Armyworm populations, but most of them have not been tested in the field and do not include one of the most important variables that influence insect development: the temperature. In this study, we developed a computational model that is able to represent the spatio-temporal dynamics of fall Armyworms in agricultural landscapes composed of Bt and non- Bt areas, allowing the user to define different input variables, such as the crop area, thermal requirements of S. frugiperda , migration rate, rate of larval movement, and insect resistance to transgenic crops. In order to determine the efficiency of the proposed model, we fitted it using a 4-year (2012–2015) FAW monitoring data for an area located in northern Florida, USA. Simulations were run to predict the number of adults in 2016 and examine possible scenarios involving climate change. The model satisfactorily described the main outbreaks of fall Armyworms, estimating values for parameters associated with insect dynamics, i.e., resistance-allele frequency (0.15), migration rate (0.48) and rate of larval movement (0.04). A posterior sensitivity analysis indicated that the frequency of the resistance allele most influenced the model, followed by the migration rate. Our simulations indicated that an increase of 1 °C in weekly mean temperatures could almost double the levels of fall Armyworm populations, drawing attention to the possible consequences of temperature rises for pest dynamics.
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inferring the annual migration patterns of fall Armyworm lepidoptera noctuidae in the united states from mitochondrial haplotypes
Ecology and Evolution, 2012Co-Authors: Rodney N Nagoshi, Robert L Meagher, Mirian M HayroeAbstract:Spodoptera frugiperda (J. E. Smith) or fall Armyworm is an important agricultural pest of a number of crops in the western hemisphere. In the United States, infestations in corn acreages extend from the Mexican to the Canadian border. Because fall Armyworm does not survive prolonged freezing, the infestations annually affecting most of North America are migrants from southern Texas and Florida, where winter temperatures are mild and host plants are available. A 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 United States 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.
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puerto rico fall Armyworm has only limited interactions with those from brazil or texas but could have substantial exchanges with florida populations
Journal of Economic Entomology, 2010Co-Authors: Rodney N Nagoshi, Robert L Meagher, David A JenkinsAbstract:Fall Armyworm, Spodoptera frugiperda (J.E. Smith) (Lepidoptera: Noctuidae), is an important agricultural pest that is endemic to Puerto Rico and the rest of the Caribbean islands. Relatively little is known about the population movements of fall Armyworm in the Caribbean and the magnitude of genetic interactions, if any, with populations from North, South, and Central America. To address this issue, a novel method involving mitochondrial haplotype ratios currently being used to study the migration of fall Armyworm in North America was applied to populations in Puerto Rico. The results indicate limited interactions between Puerto Rico fall Armyworm and those from Brazil or Texas but the potential for significant exchanges with populations in Florida.
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texas is the overwintering source of fall Armyworm in central pennsylvania implications for migration into the northeastern united states
Environmental Entomology, 2009Co-Authors: Rodney N Nagoshi, S. J. Fleischer, Robert L MeagherAbstract:Fall Armyworm, Spodoptera frugiperda (J. E. Smith) (Lepidoptera: Noctuidae), infestations in most of North America arise from annual migrations of populations that overwinter in southern Texas and Florida. Cytochrome oxidase I haplotype profiles within the fall Armyworm corn strain, the subgroup that preferentially infests corn (Zea mays L.), can differentiate the Texas and Florida populations. We use this molecular metric to show that fall Armyworms in central Pennsylvania originate from Texas, indicating the existence of a migratory pathway from Texas to the northeastern United States. These results were compared with historical trapping data for fall Armyworm and another migratory noctuid, corn earworm Helicoverpa zea (Boddie) (Lepidoptera: Noctuidae), in the Pennsylvania and Maryland corn-producing areas to better define lepidopteran migratory pathways.
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Parasitized and non-parasitized prey selectivity by an insectivorous bird
Crop Protection, 2005Co-Authors: Gregory A. Jones, Kathryn E. Sieving, Michael L. Avery, Robert L MeagherAbstract:Abstract The identification and conservation of naturally occurring enemies of crop pests is an important means of improving biological control in cropping systems. One particularly important potential mechanism whereby birds might stabilize and improve pest control is consumption of individual prey that escape mortality from other agents of biological control. We tested the hypothesis that birds prefer to forage upon non-parasitized fall Armyworm ( Spodoptera frugiperda J. E. Smith) prey via captive feeding trials, where birds were also offered Armyworms parasitized by Euplectrus plathypenae (Howard) larvae. While birds were equally willing to eat both parasitized and non-parasitized Armyworm prey of the same body size, they strongly preferred larger non-parasitized prey. This preference continued even as this prey item became less numerous than smaller parasitized worms during feeding trials. Our results suggest that birds may contribute to the biological control of arthropod pests that escape control, become larger in body size and, subsequently, a favored prey item.
Rodney N Nagoshi - One of the best experts on this subject based on the ideXlab platform.
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Genetic characterization of fall Armyworm ( Spodoptera frugiperda ) in Ecuador and comparisons with regional populations identify likely migratory relationships
PLOS ONE, 2019Co-Authors: Rodney N Nagoshi, Benjamin Y. Nagoshi, Ernesto Cañarte, Bernardo Navarrete, Ramón Solórzano, Sandra Garcés-carreraAbstract:Fall Armyworm, Spodoptera frugiperda (J. E. Smith), is an important agricultural pest native to the Americas that has recently been introduced into the Eastern Hemisphere where it has spread rapidly through most of Africa and much of Asia. The long-term economic consequences of this invasion will depend on how the species and important subpopulations become distributed upon reaching equilibrium, which is expected to be influenced by a number of factors including climate, geography, agricultural practices, and seasonal winds, among others. Much of our understanding of fall Armyworm movements have come from mapping genetically defined subpopulations in the Western Hemisphere, particularly in North America where annual long-distance migrations of thousands of kilometers have been documented and modeled. In contrast, fall Armyworm mapping in much of the rest of the hemisphere is relatively incomplete, with the northern portion of South America particularly lacking despite its potential importance for understanding fall Armyworm migration patterns. Here we describe the first genetic description of fall Armyworm infesting corn in Ecuador, which lies near a likely migration conduit based on the location of regional trade winds. The results were compared with populations from corn habitats in select locations in the Caribbean and South America to investigate the possible migratory relationship between these populations and was further assessed with respect to prevailing wind patterns and the distribution of locations with climate favorable for fall Armyworm population establishment and growth.
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inferring the annual migration patterns of fall Armyworm lepidoptera noctuidae in the united states from mitochondrial haplotypes
Ecology and Evolution, 2012Co-Authors: Rodney N Nagoshi, Robert L Meagher, Mirian M HayroeAbstract:Spodoptera frugiperda (J. E. Smith) or fall Armyworm is an important agricultural pest of a number of crops in the western hemisphere. In the United States, infestations in corn acreages extend from the Mexican to the Canadian border. Because fall Armyworm does not survive prolonged freezing, the infestations annually affecting most of North America are migrants from southern Texas and Florida, where winter temperatures are mild and host plants are available. A 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 United States 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.
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puerto rico fall Armyworm has only limited interactions with those from brazil or texas but could have substantial exchanges with florida populations
Journal of Economic Entomology, 2010Co-Authors: Rodney N Nagoshi, Robert L Meagher, David A JenkinsAbstract:Fall Armyworm, Spodoptera frugiperda (J.E. Smith) (Lepidoptera: Noctuidae), is an important agricultural pest that is endemic to Puerto Rico and the rest of the Caribbean islands. Relatively little is known about the population movements of fall Armyworm in the Caribbean and the magnitude of genetic interactions, if any, with populations from North, South, and Central America. To address this issue, a novel method involving mitochondrial haplotype ratios currently being used to study the migration of fall Armyworm in North America was applied to populations in Puerto Rico. The results indicate limited interactions between Puerto Rico fall Armyworm and those from Brazil or Texas but the potential for significant exchanges with populations in Florida.
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texas is the overwintering source of fall Armyworm in central pennsylvania implications for migration into the northeastern united states
Environmental Entomology, 2009Co-Authors: Rodney N Nagoshi, S. J. Fleischer, Robert L MeagherAbstract:Fall Armyworm, Spodoptera frugiperda (J. E. Smith) (Lepidoptera: Noctuidae), infestations in most of North America arise from annual migrations of populations that overwinter in southern Texas and Florida. Cytochrome oxidase I haplotype profiles within the fall Armyworm corn strain, the subgroup that preferentially infests corn (Zea mays L.), can differentiate the Texas and Florida populations. We use this molecular metric to show that fall Armyworms in central Pennsylvania originate from Texas, indicating the existence of a migratory pathway from Texas to the northeastern United States. These results were compared with historical trapping data for fall Armyworm and another migratory noctuid, corn earworm Helicoverpa zea (Boddie) (Lepidoptera: Noctuidae), in the Pennsylvania and Maryland corn-producing areas to better define lepidopteran migratory pathways.
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can the amount of corn acreage predict fall Armyworm lepidoptera noctuidae infestation levels in nearby cotton
Journal of Economic Entomology, 2009Co-Authors: Rodney N NagoshiAbstract:ABSTRACT Fall Armyworm, Spodoptera frugiperda (J.E. Smith) (Lepidoptera: Noctuidae), is a major pest of corn, Zea mays L., and a significant, but more sporadic, pest of cotton, Gossypium hirsutum L., in the Western Hemisphere. Previous studies showed that the cotton infestations primarily involve a fall Armyworm subpopulation known as the “corn-strain” for which corn is the preferred host plant. It was suggested that the fall Armyworm infesting cotton originated in corn and spread into secondary hosts as their numbers increased. In this study, high positive correlations were found between corn acreage and fall Armyworm infestation levels in cotton. These occurred between areas that are either geographically close or along plausible migration pathways. Formulae were derived from scatter plot and linear regression analysis that can predict infestation levels in cotton based on corn acreage. The implications of these results for describing and predicting fall Armyworm population movements are discussed.
Mirian M Hayroe - One of the best experts on this subject based on the ideXlab platform.
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inferring the annual migration patterns of fall Armyworm lepidoptera noctuidae in the united states from mitochondrial haplotypes
Ecology and Evolution, 2012Co-Authors: Rodney N Nagoshi, Robert L Meagher, Mirian M HayroeAbstract:Spodoptera frugiperda (J. E. Smith) or fall Armyworm is an important agricultural pest of a number of crops in the western hemisphere. In the United States, infestations in corn acreages extend from the Mexican to the Canadian border. Because fall Armyworm does not survive prolonged freezing, the infestations annually affecting most of North America are migrants from southern Texas and Florida, where winter temperatures are mild and host plants are available. A 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 United States 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.
R E Jackson - One of the best experts on this subject based on the ideXlab platform.
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damage and survivorship of fall Armyworm lepidoptera noctuidae on transgenic field corn expressing bacillus thuringiensis cry proteins
Crop Protection, 2011Co-Authors: Jarrod T. Hardke, Rogers B Leonard, Fangneng Huang, R E JacksonAbstract:Field corn, Zea mays L., plants expressing Cry1Ab and Cry1F insecticidal crystal (Cry) proteins of Bacillus thuringiensis (Bt) Berliner are planted on considerable acreage across the Southern region of the United States. The fall Armyworm, Spodoptera frugiperda (J.E. Smith), is an economically important pest during the mid-to-late season on non-Bt and some commercial Bt corn hybrids. The objective of this study was to quantify foliar injury and survivorship of fall Armyworm on transgenic corn lines expressing Cry1Ab or Cry1F Bt proteins. Corn lines/hybrids expressing Cry1Ab, Cry1F, and a conventional non-Bt cultivar were evaluated against artificial infestations of fall Armyworm in field trials. Larvae (second instars) of fall Armyworm were placed on corn plants (V8-V10 stages). Leaf injury ratings were recorded 14 d after infestation. Hybrids expressing Cry1F had significantly lower feeding injury ratings than non-Bt corn plants. Development and survivorship of fall Armyworm on Bt corn lines/hybrids were also evaluated in no-choice laboratory assays by offering freshly harvested corn leaf tissue to third instars. Transgenic corn hybrids expressing Cry1Ab or Cry1F significantly reduced growth, development, and survivorship of fall Armyworm compared to those offered non-Bt corn tissue. However, 25e76% of third instars offered Bt corn leaf tissues successfully pupated and emerged as adults. These results suggest Cry1Ab has limited effects on fall Armyworm; whereas Cry1F demonstrated significant reductions in foliar injury and lower survivorship compared to that on non-Bt corn tissues. Although fall Armyworm is not considered a primary target for insect resistance management by the U.S. Environmental Protection Agency, these levels of survivorship could impact selection pressures across the farmscape, especially when considering that transgenic Bt cotton cultivars express similar Cry (Cry1Ac or Cry1F) proteins.
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damage and survivorship of fall Armyworm lepidoptera noctuidae on transgenic field corn expressing bacillus thuringiensis cry proteins
Crop Protection, 2011Co-Authors: Jarrod T. Hardke, Rogers B Leonard, Fangneng Huang, R E JacksonAbstract:Field corn, Zea mays L., plants expressing Cry1Ab and Cry1F insecticidal crystal (Cry) proteins of Bacillus thuringiensis (Bt) Berliner are planted on considerable acreage across the Southern region of the United States. The fall Armyworm, Spodoptera frugiperda (J.E. Smith), is an economically important pest during the mid-to-late season on non-Bt and some commercial Bt corn hybrids. The objective of this study was to quantify foliar injury and survivorship of fall Armyworm on transgenic corn lines expressing Cry1Ab or Cry1F Bt proteins. Corn lines/hybrids expressing Cry1Ab, Cry1F, and a conventional non-Bt cultivar were evaluated against artificial infestations of fall Armyworm in field trials. Larvae (second instars) of fall Armyworm were placed on corn plants (V8-V10 stages). Leaf injury ratings were recorded 14 d after infestation. Hybrids expressing Cry1F had significantly lower feeding injury ratings than non-Bt corn plants. Development and survivorship of fall Armyworm on Bt corn lines/hybrids were also evaluated in no-choice laboratory assays by offering freshly harvested corn leaf tissue to third instars. Transgenic corn hybrids expressing Cry1Ab or Cry1F significantly reduced growth, development, and survivorship of fall Armyworm compared to those offered non-Bt corn tissue. However, 25–76% of third instars offered Bt corn leaf tissues successfully pupated and emerged as adults. These results suggest Cry1Ab has limited effects on fall Armyworm; whereas Cry1F demonstrated significant reductions in foliar injury and lower survivorship compared to that on non-Bt corn tissues. Although fall Armyworm is not considered a primary target for insect resistance management by the U.S. Environmental Protection Agency, these levels of survivorship could impact selection pressures across the farmscape, especially when considering that transgenic Bt cotton cultivars express similar Cry (Cry1Ac or Cry1F) proteins.
Patrick J. Moran - One of the best experts on this subject based on the ideXlab platform.
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Effects of Drought Stressed Cotton, Gossypium hirsutum L., on Beet Armyworm, Spodoptera exigua (Hübner) Oviposition, and Larval Feeding Preferences and Growth
Journal of Chemical Ecology, 2003Co-Authors: Allan T. Showler, Patrick J. MoranAbstract:The beet Armyworm, Spodoptera exigua (Hübner), has been anecdotally reported to oviposit more on drought stressed than on nonstressed cotton plants. Using potted cotton plants in cages, this study demonstrated that beet Armyworms deposited 3.3, 4.6, and 2.3 times more ( P ≤ 0.05) eggs on cotton plants that were grown on 1500, 1000, and 750 ml water/wk, respectively, than on cotton plants grown in well watered (4000 ml water/wk) soil. Third instars, however, showed no preference for stressed cotton foliage over nonstressed foliage. Third instar beet Armyworms raised on well watered cotton plants were 1.5, 2.3, and 2.6 times heavier than those reared on cotton grown in the 1500, 1000, and 750 ml water/wk plants ( P ≤ 0.05), respectively. Physiochemical analyses showed that drought stressed leaves had significantly greater accumulations of free amino acids that are essential for insect growth and development. Soluble protein and soluble carbohydrates were also more abundant in stressed leaves compared to nonstressed leaves. Despite the apparent increase in nutritional quality in drought stressed plants, larval survival was reduced, probably because the limiting factor became water. Greater amounts of cotton leaf area were consumed from drought stressed leaves ( P ≤ 0.05) than from nonstressed leaves, probably because the larvae had to metabolize greater portions of assimilated energy to supplement body water with metabolic water derived from respiration. The association of greater host plant nutritional quality to oviposition preference, and conversely, to reduced survivorship, is discussed.