scholarly journals Rapid identification of the invasive fall armyworm Spodoptera frugiperda (Lepidoptera, Noctuidae) using species-specific primers in multiplex PCR

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Cheng-Lung Tsai ◽  
I.-Hsuan Chu ◽  
Ming-Hsun Chou ◽  
Theeraphap Chareonviriyaphap ◽  
Ming-Yao Chiang ◽  
...  
Keyword(s):  
Spodoptera Frugiperda ◽  
Egg Production ◽  
Mainland China ◽  
Fall Armyworm ◽  
The United States ◽  
Rapid Identification ◽  
Economic Losses ◽  
Specific Primers ◽  
Wide Range ◽  
Species Specific

Abstract The fall armyworm (FAW), Spodoptera frugiperda (Smith), is a major pest native to the Americas. A recent invasion of FAWs from Africa eastward to South Asia, the Indochina Peninsula, and mainland China has received much attention due to the considerable economic losses in agriculture. FAWs can rapidly colonise a new area, likely due to the wide range of host plants, good flying capability, and high egg production. Therefore, a convenient, quick, and accurate tool for FAW identification is urgently required to establish a FAW invasion management strategy. In this study, FAW-specific primers were designed to recognise FAWs on the basis of internal transcribed spacer 1 (ITS1). The results revealed the accurate FAW recognition of the three congeneric species and eight common corn lepidopteran pests, especially at their larval stage. Furthermore, species-specific primers have confirmed their efficacy by using 69 FAW specimens from Taiwan, Thailand, and the United States, with a 96% success rate, excluding 3 decayed specimens. By using the simple, reliable, and convenient FAW-specific primers, a pest management programme can be developed not only to reduce sequencing costs and experimental time from 2 days to 4 h, but eradicate the FAW as soon as it enters a new area.

Species-specific duplex PCR for the detection of Pratylenchus penetrans

Nematology ◽  
2009 ◽  
Vol 11 (6) ◽  
pp. 847-857 ◽  
Author(s):  
Lieven Waeyenberge ◽  
Nicole Viaene ◽  
Maurice Moens
Keyword(s):  
Internal Control ◽  
Dna Sequences ◽  
Rrna Gene ◽  
Duplex Pcr ◽  
Specific Primers ◽  
5.8S Rrna Gene ◽  
5.8S Rrna ◽  
Wide Range ◽  
Pcr Products ◽  
Species Specific

Abstract ITS1, the 5.8S rRNA gene and ITS2 of the rDNA region were sequenced from 20 different Pratylenchus species. Additionally, the same region was sequenced from seven populations of P. penetrans. After purifying, cloning and sequencing the PCR products, all sequences were aligned in order to find unique sites suitable for the design of species-specific primers for P. penetrans. Since ITS regions showed variability between and even within populations of P. penetrans, only three small DNA sequences were suitable for the construction of three potentially useful species-specific primers. New species-specific primers were paired with existing universal ITS primers and tested in all possible primer combinations. The best performing primer set, supplemented with a universal 28S rDNA primer set that served as an internal control, was tested in duplex PCR. The ideal annealing temperature, Mg2+ concentration and primer ratios were then determined for the most promising primer set. The optimised duplex PCR was subsequently tested on a wide range of different Pratylenchus spp. and 25 P. penetrans populations originating from all over the world. To test the sensitivity, the duplex PCR was conducted on DNA extracted from a single P. penetrans nematode mixed with varying amounts of nematodes belonging to another Pratylenchus species. Results showed that a reliable and sensitive P. penetrans species-specific duplex PCR was constructed.

Virulence and Genetic Characterization of Six Baculovirus Strains Isolated From Different Populations of Spodoptera Frugiperda (Lepidoptera: Noctuidae)

2021 ◽  
Author(s):  
Ingrid Zanella-Saenz ◽  
Elisabeth A. Herniou ◽  
Jorge E. Ibarra ◽  
Ma.Cristina Del Rincón-Castro ◽  
Ilse Alejandra Huerta-Arredondo
Keyword(s):  
Biological Control ◽  
Cell Cultures ◽  
Spodoptera Frugiperda ◽  
Fall Armyworm ◽  
The United States ◽  
Infection Mechanisms ◽  
Different Populations

Abstract Fall armyworm (FAW), Spodoptera frugiperda (Smith, 1797), is a polyphagous, voracious, and economically important agricultural pest. Biological control of FAW is a strategy that must be further explored. This study evaluated six baculovirus strains isolated from infected FAW larvae from Mexico, Argentina, Honduras, and the United States. Five alphabaculoviruses (SfNPV-An2, SfNPV-Arg, SfNPV-Fx, SfNPV-Ho and SfNPV-Sin) and one betabaculovirus (SfGV-RV), were tested against FAW larvae, showing a wide diversity of virulence levels among strains when their estimated LC50s were compared, being SfNPVArg, SfNPV-Ho and SfNPV-Fx more virulent than SfNPV-An 2 , SfNPV-Sin and SfGV-RV. To determine any virulence difference in vitro studies of these isolates, Sf9 cell cultures were used. Interestingly, only ODVs from four of the test SfNPV strains showed infectivity on Sf9 cell cultures, and some differences in virulence were observed. Genomic restriction analyses and partial sequences of lef-8, lef-9 , and polh/granulin genes showed little variability among alphabaculoviruses, both, among them and with previously reported sequences. However, sequences from SfGV-RV were closer to previously reported sequences from the SfGVVG008 strain than the SfGV-Arg and SfGV-VG014 strains. The great difference in the in vivo virulence was not correlated with great similarity among the isolates. The characterization of these six baculoviruses isolates offers the basis for exploring their potential as biological control agents against S. frugiperda, as well the initial studies on their specific infection mechanisms, evolution, and ecology.

scholarly journals Whole genome comparisons reveal panmixia among fall armyworm (Spodoptera frugiperda) from diverse locations

2020 ◽  
Author(s):  
Katrina A. Schlum ◽  
Kurt Lamour ◽  
Caroline Placidi de Bortoli ◽  
Rahul Banerjee ◽  
Scott J. Emrich ◽  
...  
Keyword(s):  
United States ◽  
Puerto Rico ◽  
Gene Flow ◽  
Spodoptera Frugiperda ◽  
Fall Armyworm ◽  
The United States ◽  
Genomic Diversity ◽  
Whole Genome ◽  
Long Distance ◽  
Host Strains

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.

scholarly journals Whole genome comparisons reveal panmixia among fall armyworm (Spodoptera frugiperda) from diverse locations

BMC Genomics ◽  
2021 ◽  
Vol 22 (1) ◽  
Author(s):  
Katrina A. Schlum ◽  
Kurt Lamour ◽  
Caroline Placidi de Bortoli ◽  
Rahul Banerjee ◽  
Robert Meagher ◽  
...  
Keyword(s):  
United States ◽  
Puerto Rico ◽  
Gene Flow ◽  
Spodoptera Frugiperda ◽  
Fall Armyworm ◽  
The United States ◽  
Whole Genome ◽  
Long Distance ◽  
Field Samples ◽  
Host Strains

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.

Dispersal and Seasonal Occurrence of Noctuidonema guyanense, an Ectoparasitic Nematode of Adult Fall Armyworm (Lepidoptera: Noctuidae), in the United States2

1991 ◽  
Vol 26 (1) ◽  
pp. 136-148 ◽  
Author(s):  
Alvin M. Simmons ◽  
Charlie E. Rogers
Keyword(s):  
Spodoptera Frugiperda ◽  
Gulf Coast ◽  
Fall Armyworm ◽  
The United States ◽  
Adult Males ◽  
West Texas ◽  
Percent Parasitism ◽  
Important Regulator ◽  
Lepidoptera Noctuidae ◽  
Eastern Half

Migrant Spodoptera frugiperda (J. E. Smith) adult males were collected at 17 widely separated locations throughout the eastern half of the United States and were examined to determine if Noctuidonema guyanense Remillet and Silvain, an ectoparasitic nematode of adult Lepidoptera, were transported with the host. Nematodes were recovered from all locations where moths were captured. Nematode populations and parasitism of fall armyworm males were higher in the eastern states than in the Plains, Midwestern, and Central states (e.g., west Texas, Iowa, and Ohio). Percent parasitism and the number of nematodes per infested fall armyworm changed over time at each location. The initial immigrant fall armyworm males at a given location generally had few or no nematodes. These data suggest that moths with a moderate number of nematodes may be less able to disperse. Nematode populations peaked in mid-to-late August and then declined to a few or none by mid-October at locations north of the Gulf Coast area. Among other factors, temperature is apparently an important regulator of N. guyanense populations.

scholarly journals Advances in Research on Phytophthora capsici on Vegetable Crops in The United States

Plant Disease ◽  
2012 ◽  
Vol 96 (11) ◽  
pp. 1588-1600 ◽  
Author(s):  
Leah L. Granke ◽  
Lina Quesada-Ocampo ◽  
Kurt Lamour ◽  
Mary K. Hausbeck
Keyword(s):  
Host Range ◽  
Phytophthora Capsici ◽  
The United States ◽  
Fruit Rot ◽  
Economic Losses ◽  
Future Research ◽  
Vegetable Crops ◽  
Long Distance ◽  
Term Survival ◽  
Wide Range

Since L. H. Leonian's first description of Phytophthora capsici as a pathogen of chile pepper in 1922, we have made many advances in our understanding of this pathogen's biology, host range, dissemination, and management. P. capsici causes foliar blighting, damping-off, wilting, and root, stem, and fruit rot of susceptible hosts, and economic losses are experienced annually in vegetable crops including cucurbits and peppers. Symptoms of P. capsici infection may manifest as stunting, girdling, or cankers for some cultivars or crops that are less susceptible. P. capsici continues to be a constraint on production, and implementation of an aggressive integrated management scheme can still result in insufficient control when weather is favorable for disease. Management of diseases caused by P. capsici is currently limited by the long-term survival of the pathogen as oospores in the soil, a wide host range, long-distance movement of the pathogen in surface water used for irrigation, the presence of fungicide-resistant pathogen populations, and a lack of commercially acceptable resistant host varieties. P. capsici can infect a wide range of hosts under laboratory and greenhouse conditions including cultivated crops, ornamentals, and native plants belonging to diverse plant families. As our understanding of P. capsici continues to grow, future research should focus on developing novel and effective solutions to manage this pathogen and prevent economic losses due to the diseases it causes.

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