The Experts below are selected from a list of 288 Experts worldwide ranked by ideXlab platform
George G Kennedy - One of the best experts on this subject based on the ideXlab platform.
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understanding the potential impact of continued seed treatment use for resistance management in cry51aa2 834_16 bt cotton against Frankliniella fusca
PLOS ONE, 2020Co-Authors: Anders S Huseth, Damon A Dambrosio, George G KennedyAbstract:Transgenic cotton expressing Cry51Aa2.834_16 Bt toxin (hereafter referred to as MON 88702) has the potential to be an important tool for pest management due to its unique activity against tobacco thrips, Frankliniella fusca. Unlike other Bt toxins targeting lepidopteran cotton pests, MON 88702 does not cause direct mortality but has an antixenotic effect that suppresses F. fusca oviposition. Previous work has shown neonicotinoid seed treated (NST) crops have similar behavioral effects on thrips. This study used non-choice and common garden experiments to examine how the presence of MON 88702 cotton and soybean (another F. fusca host) with and without NSTs might alter F. fusca infestation distributions. In a no-choice environment, significant larval establishment differences were observed, with untreated soybean plants becoming most heavily infested. In choice experiments, plants expressing MON 88702 or were neonicotinoid treated had significantly lower larval establishment. Larval density decreased as dispersal distance increased, suggesting reproductive decisions were negatively related to distance from the release point. Understanding how F. fusca responds to MON 88702 in an environment where adults can choose among multiple host plants will provide valuable context for projections regarding design of MON 88702 resistance refuges. Reduced larval establishment on NST cotton and soybean suggests that area-wide use of NSTs could reduce the number of susceptible F. fusca generated in unstructured crop refuges for MON 88702. These results also suggest that although the presence of NST MON 88702 could suppress reproduction and resistance selection, over time this benefit could erode resulting in increased larval establishment on NST cotton and soybean due to increased frequency of neonicotinoid resistant F. fusca populations.
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cotton thrips infestation predictor a practical tool for predicting tobacco thrips Frankliniella fusca infestation of cotton seedlings in the south eastern united states
Pest Management Science, 2020Co-Authors: Thomas M Chappell, Jeremy K Greene, Rebecca Ward, Kelley T Depolt, Phillip M Roberts, George G KennedyAbstract:BACKGROUND Thrips (order Thysanoptera) infestations of cotton seedlings result in plant injury, increasing the detrimental consequences of other challenges to production agriculture, such as abiotic stress or infestation by other pests. Using Frankliniella fusca as a thrips species of focus, we empirically developed a composite model of thrips phenology and cotton seedling susceptibility to predict site-specific infestation risk so that monitoring and other resources can be allocated efficiently, to optimize the timing of thrips control measures to maximize effectiveness, and to inform stakeholders about the dynamics of thrips infestation and cotton seedling injury at a time when thrips are evolving resistance to commonly-used pesticides. RESULTS A mixture distribution model of thrips infestation potential, fit to data describing F. fusca adult dispersal in time, proved best for predicting infestations of F. fusca on cotton seedlings. Thrips generations occurring each year as a function of weather are represented as a probability distribution. A model of cotton seedling growth was also developed to predict susceptibility as a function of weather. Combining these two models resulted in a model of seedling injury, which was validated and developed for implementation as a software tool. CONCLUSIONS Experimental validation of the implemented model demonstrated the utility of its output in predicting infestation risk. Successful implementation and use of the software tool derived from this model was enabled by close cooperation with university extension personnel, agricultural consultants, and growers, underscoring the importance of stakeholder and expert input to the success of applied analytical research. © 2020 Society of Chemical Industry.
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feeding behavior of Frankliniella fusca on seedling cotton expressing cry51aa2 834_16 bt toxin
Pest Management Science, 2020Co-Authors: Damon A Dambrosio, George G Kennedy, Anders S HusethAbstract:Background Tobacco thrips, Frankliniella fusca (Hinds), is a pest of cotton. Currently, growers rely on neonicotinoid seed treatments to control F. fusca. However, the occurrence of neonicotinoid-resistant F. fusca populations has created new challenges for their management. Development of thrips-active Cry51Aa2.834_16 Bacillus thuringiensis (Bt) toxin expressed in MON 88702 cotton will be an important new tactic for thrips management. Previous studies have shown that MON 88702 causes limited mortality of F. fusca adults and larvae but reduces infestations on seedling cotton by suppressing oviposition from colonizing adults. This suggests that the toxin affects host preference of adult F. fusca. Knowledge of the effect of this trait on F. fusca feeding behavior provides a more complete understanding of MON 88702 activity. Using electropenetrography, we compared the feeding behaviors of adult F. fusca females on MON 88702 cotton and a non-Bt isoline cotton over 2 h. The number of probes, proportion of probes resulting in ingestion, total duration of ingestion, and duration of ingestion per event were measured. Results On MON 88702 seedlings, F. fusca probed and ingested fewer times than those on non-Bt cotton. Probes on MON 88702 were less likely to lead to ingestion than on non-Bt cotton. The total duration of ingestion and duration of ingestion per event did not differ between treatments. Conclusion The results show that MON 88702 has an antifeedant effect on F. fusca, which provides insight into behavioral responses driving MON 88702 aversion and anti-oviposition documented in previous studies. © 2020 Society of Chemical Industry.
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Frankliniella fusca and Frankliniella occidentalis response to thrips active cry51aa2 834_16 bt cotton with and without neonicotinoid seed treatment
Crop Protection, 2020Co-Authors: Damon A Dambrosio, George G Kennedy, Anders S HusethAbstract:Abstract Frankliniella fusca (Hinds) and F. occidentalis (Pergande) are economically important thrips species in cotton production. In the Southeast and Mid-South, F. fusca is an early season seedling pest. In the West, F. occidentalis is a sporadic pest of seedling cotton and a predator of other cotton pests. A novel Bt toxin, Cry51Aa2.834_16 expressed in MON 88702 cotton, has activity against thrips and plant bugs, and will likely become an important management tool for early season pests in cotton. Determining its utility in cotton pest management requires understanding its effects on F. fusca and F. occidentalis. Individual adult female F. fusca and F. occidentalis were exposed to cotyledon disks cut from greenhouse-grown cotton expressing Cry51Aa2.834_16 (MON 88702) or a near-isoline (non-Bt) with or without an imidacloprid seed treatment. Insects were exposed for 72 h and mortality evaluated. Next, individually caged seedlings were infested with five adult female F. fusca or F. occidentalis and egg numbers counted after 72 h. Larval establishment determined after 10 days for F. fusca or 7 days for F. occidentalis. Exposure to MON 88702 in the absence of the imidacloprid seed treatment caused significant adult mortality in F. occidentalis. Exposure to the imidacloprid seed treatment caused significant adult mortality in both species on both MON 88702 and non-Bt cotton plants. Oviposition and larval establishment were reduced by both MON 88702 as well as imidacloprid seed treatment in both species, but the effect size differed between species. In F. fusca, the imidacloprid seed treatment caused the greatest reductions, whereas in F. occidentalis, MON 88702 had the greater effect.
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stability of neonicotinoid sensitivity in Frankliniella fusca populations found in agroecosystems of the southeastern usa
Pest Management Science, 2019Co-Authors: Thomas M Chappell, Anders S Huseth, George G KennedyAbstract:BACKGROUND Insecticide resistance arises at a given location in response to selection acting on novel genotypes or standing variation, or allelic migration. Fitness costs of resistance may slow resistance evolution or result in reversion to susceptibility, but consistent and geographically widespread use of insecticides may provide sufficient selection to offset the fitness costs of resistance. Understanding this relationship is important to the success of insecticide resistance management. We report the existence of fitness costs of neonicotinoid resistance in field-collected populations of the tobacco thrips (Frankliniella fusca), which increasingly challenge upland cotton production in the southeastern USA. RESULTS Populations (14 of 15 in 2015; 4 of 5 in 2016) investigated showed a loss of resistance to imidacloprid after multiple generations without exposure to the insecticide. Populations studied in 2016 were each split into two colonies, and one of each pair was repeatedly exposed to imidacloprid. In three of the four populations that lost resistance, imidacloprid-exposed colonies lost resistance significantly more slowly than did corresponding unexposed colonies. CONCLUSION For imidacloprid resistance to be broadly increasing in the landscapes of the southeastern USA despite fitness costs of resistance, selection for resistance must be sufficient to overcome the costs. Findings encourage investigation into why costs are overcome in this system, potentially including geographic extent of neonicotinoid use or prevalence of low-dose exposure. © 2019 Society of Chemical Industry.
Anders S Huseth - One of the best experts on this subject based on the ideXlab platform.
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understanding the potential impact of continued seed treatment use for resistance management in cry51aa2 834_16 bt cotton against Frankliniella fusca
PLOS ONE, 2020Co-Authors: Anders S Huseth, Damon A Dambrosio, George G KennedyAbstract:Transgenic cotton expressing Cry51Aa2.834_16 Bt toxin (hereafter referred to as MON 88702) has the potential to be an important tool for pest management due to its unique activity against tobacco thrips, Frankliniella fusca. Unlike other Bt toxins targeting lepidopteran cotton pests, MON 88702 does not cause direct mortality but has an antixenotic effect that suppresses F. fusca oviposition. Previous work has shown neonicotinoid seed treated (NST) crops have similar behavioral effects on thrips. This study used non-choice and common garden experiments to examine how the presence of MON 88702 cotton and soybean (another F. fusca host) with and without NSTs might alter F. fusca infestation distributions. In a no-choice environment, significant larval establishment differences were observed, with untreated soybean plants becoming most heavily infested. In choice experiments, plants expressing MON 88702 or were neonicotinoid treated had significantly lower larval establishment. Larval density decreased as dispersal distance increased, suggesting reproductive decisions were negatively related to distance from the release point. Understanding how F. fusca responds to MON 88702 in an environment where adults can choose among multiple host plants will provide valuable context for projections regarding design of MON 88702 resistance refuges. Reduced larval establishment on NST cotton and soybean suggests that area-wide use of NSTs could reduce the number of susceptible F. fusca generated in unstructured crop refuges for MON 88702. These results also suggest that although the presence of NST MON 88702 could suppress reproduction and resistance selection, over time this benefit could erode resulting in increased larval establishment on NST cotton and soybean due to increased frequency of neonicotinoid resistant F. fusca populations.
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feeding behavior of Frankliniella fusca on seedling cotton expressing cry51aa2 834_16 bt toxin
Pest Management Science, 2020Co-Authors: Damon A Dambrosio, George G Kennedy, Anders S HusethAbstract:Background Tobacco thrips, Frankliniella fusca (Hinds), is a pest of cotton. Currently, growers rely on neonicotinoid seed treatments to control F. fusca. However, the occurrence of neonicotinoid-resistant F. fusca populations has created new challenges for their management. Development of thrips-active Cry51Aa2.834_16 Bacillus thuringiensis (Bt) toxin expressed in MON 88702 cotton will be an important new tactic for thrips management. Previous studies have shown that MON 88702 causes limited mortality of F. fusca adults and larvae but reduces infestations on seedling cotton by suppressing oviposition from colonizing adults. This suggests that the toxin affects host preference of adult F. fusca. Knowledge of the effect of this trait on F. fusca feeding behavior provides a more complete understanding of MON 88702 activity. Using electropenetrography, we compared the feeding behaviors of adult F. fusca females on MON 88702 cotton and a non-Bt isoline cotton over 2 h. The number of probes, proportion of probes resulting in ingestion, total duration of ingestion, and duration of ingestion per event were measured. Results On MON 88702 seedlings, F. fusca probed and ingested fewer times than those on non-Bt cotton. Probes on MON 88702 were less likely to lead to ingestion than on non-Bt cotton. The total duration of ingestion and duration of ingestion per event did not differ between treatments. Conclusion The results show that MON 88702 has an antifeedant effect on F. fusca, which provides insight into behavioral responses driving MON 88702 aversion and anti-oviposition documented in previous studies. © 2020 Society of Chemical Industry.
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Frankliniella fusca and Frankliniella occidentalis response to thrips active cry51aa2 834_16 bt cotton with and without neonicotinoid seed treatment
Crop Protection, 2020Co-Authors: Damon A Dambrosio, George G Kennedy, Anders S HusethAbstract:Abstract Frankliniella fusca (Hinds) and F. occidentalis (Pergande) are economically important thrips species in cotton production. In the Southeast and Mid-South, F. fusca is an early season seedling pest. In the West, F. occidentalis is a sporadic pest of seedling cotton and a predator of other cotton pests. A novel Bt toxin, Cry51Aa2.834_16 expressed in MON 88702 cotton, has activity against thrips and plant bugs, and will likely become an important management tool for early season pests in cotton. Determining its utility in cotton pest management requires understanding its effects on F. fusca and F. occidentalis. Individual adult female F. fusca and F. occidentalis were exposed to cotyledon disks cut from greenhouse-grown cotton expressing Cry51Aa2.834_16 (MON 88702) or a near-isoline (non-Bt) with or without an imidacloprid seed treatment. Insects were exposed for 72 h and mortality evaluated. Next, individually caged seedlings were infested with five adult female F. fusca or F. occidentalis and egg numbers counted after 72 h. Larval establishment determined after 10 days for F. fusca or 7 days for F. occidentalis. Exposure to MON 88702 in the absence of the imidacloprid seed treatment caused significant adult mortality in F. occidentalis. Exposure to the imidacloprid seed treatment caused significant adult mortality in both species on both MON 88702 and non-Bt cotton plants. Oviposition and larval establishment were reduced by both MON 88702 as well as imidacloprid seed treatment in both species, but the effect size differed between species. In F. fusca, the imidacloprid seed treatment caused the greatest reductions, whereas in F. occidentalis, MON 88702 had the greater effect.
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stability of neonicotinoid sensitivity in Frankliniella fusca populations found in agroecosystems of the southeastern usa
Pest Management Science, 2019Co-Authors: Thomas M Chappell, Anders S Huseth, George G KennedyAbstract:BACKGROUND Insecticide resistance arises at a given location in response to selection acting on novel genotypes or standing variation, or allelic migration. Fitness costs of resistance may slow resistance evolution or result in reversion to susceptibility, but consistent and geographically widespread use of insecticides may provide sufficient selection to offset the fitness costs of resistance. Understanding this relationship is important to the success of insecticide resistance management. We report the existence of fitness costs of neonicotinoid resistance in field-collected populations of the tobacco thrips (Frankliniella fusca), which increasingly challenge upland cotton production in the southeastern USA. RESULTS Populations (14 of 15 in 2015; 4 of 5 in 2016) investigated showed a loss of resistance to imidacloprid after multiple generations without exposure to the insecticide. Populations studied in 2016 were each split into two colonies, and one of each pair was repeatedly exposed to imidacloprid. In three of the four populations that lost resistance, imidacloprid-exposed colonies lost resistance significantly more slowly than did corresponding unexposed colonies. CONCLUSION For imidacloprid resistance to be broadly increasing in the landscapes of the southeastern USA despite fitness costs of resistance, selection for resistance must be sufficient to overcome the costs. Findings encourage investigation into why costs are overcome in this system, potentially including geographic extent of neonicotinoid use or prevalence of low-dose exposure. © 2019 Society of Chemical Industry.
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determining Frankliniella fusca thysanoptera thripidae egg distribution in neonicotinoid seed treated cotton
Journal of Economic Entomology, 2019Co-Authors: Damon A Dambrosio, Anders S Huseth, George G KennedyAbstract:Frankliniella fusca (Hinds) (Thysanoptera: Thripidae) is an early-season cotton pest. Seedlings are injured by larvae, which hatch from eggs oviposited into seedlings and feed on developing plant tissue. Better understanding F. fusca oviposition in cotton may improve their management and address new challenges such as resistance to neonicotinoid seed treatments (NSTs). Cotton seedlings exposed to F. fusca were either cleared and stained to determine egg density and location, or dissected and washed to determine larval distribution. Experiments were conducted in the greenhouse with a susceptible population and field with a NST-resistant population. Eggs of both populations were recovered predominantly in cotyledons. Larvae were more uniformly distributed on seedlings. On NST seedlings, oviposition by the susceptible population was reduced and preference shifted to true leaves. NSTs did not alter egg placement by the resistant population. These findings suggest that injury to cotton seedlings is primarily caused by F. fusca emerging on the cotyledons, and then moving to developing leaves. The oviposition shift in NST plants correlates with how systemic NSTs have been reported to concentrate in cotyledons. This can better inform management tactics in cotton, such as well-timed foliar sprays, which, given the current resistance issue, are needed to maintain effective thrips management.
Rajagopalbabu Srinivasan - One of the best experts on this subject based on the ideXlab platform.
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virulence of entomopathogenic nematodes to pupae of Frankliniella fusca thysanoptera thripidae
Journal of Economic Entomology, 2021Co-Authors: Sehrish Gulzar, Michael D Toews, Rajagopalbabu Srinivasan, Muhammad Usman, Waqas Wakil, Camila Oliveirahofman, David I ShapiroilanAbstract:Tobacco thrips, Frankliniella fusca (Hinds) is an economically significant pest. Entomopathogenic nematodes (EPNs) have shown promise as biocontrol agents against certain thrips species, but they have not been explored for suppression of F. fusca. We investigated the potential of EPNs to manage F. fusca by conducting three different bioassays: 1) a small cup dose-response bioassay (25, 50, and 100 IJs cm-2) with four EPN species, 2) a broad virulence bioassay with eight EPN species at 100 IJs cm-2, and 3) a potted soil bioassay testing with four EPN species (100 IJs cm-2). In the dose-response bioassay, all treatments showed relatively lower adult emergence when compared with the control group, but the minimum adult emergence (30%) was observed at 7 d post-treatment when Heterorhabditis bacteriophora (FL1-1) was applied at the highest rate (100 IJs cm-2). In the broad virulence study, all EPN treatments caused significant reductions in F. fusca adult emergence (18.3-75.0%) in comparison with the control. H. bacteriophora (Fl1-1) was more virulent than other nematode treatments but statistically not different from Steinernema feltiae and Steinernema riobrave, while Steinernema rarum was the least virulent. In the potted soil bioassay, the lowest emergence (10.6%) was observed in H. bacteriophora (Fl1-1) treatment, followed by S. feltiae (SN), S. riobrave (355), and Heterorhabditis indica (HOM1) treatments. These results indicate that EPNs have the ability to suppress the soil dwelling stage of F. fusca and should be explored further under greenhouse and field conditions for biocontrol potential within an integrated pest management (IPM) context.
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evaluation of alternatives to an organophosphate insecticide with selected cultural practices effects on thrips Frankliniella fusca and incidence of spotted wilt in peanut farmscapes
Journal of Economic Entomology, 2018Co-Authors: K Marasigan, Michael D Toews, Robert C Kemerait, Mark R Abney, A K Culbreath, Rajagopalbabu SrinivasanAbstract:Peanut growers use a combination of tactics to manage spotted wilt disease caused by thrips-transmitted Tomato spotted wilt virus (TSWV). They include planting TSWV-resistant cultivars, application of insecticides, and various cultural practices. Two commonly used insecticides against thrips are aldicarb and phorate. Both insecticides exhibit broad-spectrum toxicity. Recent research has led to the identification of potential alternatives to aldicarb and phorate. In this study, along with reduced-risk, alternative insecticides, we evaluated the effect of conventional versus strip tillage; single versus twin row seeding pattern; and 13 seed/m versus 20 seed/m on thips density, feeding injury, and spotted wilt incidence. Three field trials were conducted in Georgia in 2012 and 2013. Thrips counts, thrips feeding injuriy, and incidence of spotted wilt were less under strip tillage than under conventional tillage. Reduced feeding injury from thrips was observed on twin-row plots compared with single-row plots. Thrips counts, thrips feeding injury, and incidence of spotted wilt did not vary by seeding rate. Yield from twin-row plots was greater than yield from single-row plots only in 2012. Yield was not affected by other cultural practices. Alternative insecticides, including imidacloprid and spinetoram, were as effective as phorate in suppressing thrips and reducing incidence of spotted wilt in conjunction with cultural practices. Results suggest that cultural practices and reduced-risk insecticides (alternatives to aldicarb and phorate) can effectively suppress thrips and incidence of spotted wilt in peanut.
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transcriptome changes associated with tomato spotted wilt virus infection in various life stages of its thrips vector Frankliniella fusca hinds
Journal of General Virology, 2017Co-Authors: Anita Shrestha, A K Culbreath, Donald E Champagne, Dorith Rotenberg, Anna E Whitfield, Rajagopalbabu SrinivasanAbstract:Persistent propagative viruses maintain intricate interactions with their arthropod vectors. In this study, we investigated the transcriptome-level responses associated with a persistent propagative phytovirus infection in various life stages of its vector using an Illumina HiSeq sequencing platform. The pathosystem components included a Tospovirus, Tomato spotted wilt virus (TSWV), its insect vector, Frankliniella fusca (Hinds), and a plant host, Arachis hypogaea (L.). We assembled (de novo) reads from three developmental stage groups of virus-exposed and non-virus-exposed F. fusca into one transcriptome consisting of 72 366 contigs and identified 1161 differentially expressed (DE) contigs. The number of DE contigs was greatest in adults (female) (562) when compared with larvae (first and second instars) (395) and pupae (pre- and pupae) (204). Upregulated contigs in virus-exposed thrips had blastx annotations associated with intracellular transport and virus replication. Upregulated contigs were also assigned blastx annotations associated with immune responses, including apoptosis and phagocytosis. In virus-exposed larvae, Blast2GO analysis identified functional groups, such as multicellular development with downregulated contigs, while reproduction, embryo development and growth were identified with upregulated contigs in virus-exposed adults. This study provides insights into differences in transcriptome-level responses modulated by TSWV in various life stages of an important vector, F. fusca.
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interactions between Frankliniella fusca and pantoea ananatis in the center rot epidemic of onion allium cepa
Phytopathology, 2016Co-Authors: Bhabesh Dutta, Apurba K Barman, Utku Avci, R D Gitaitis, Kathleen Marasigan, Rajagopalbabu SrinivasanAbstract:An Enterobacteriaceae bacterium, Pantoea ananatis (Serrano) Mergaert, is the causal agent of an economically important disease of onion, center rot. P. ananatis is transmitted by an onion-infesting thrips, Frankliniella fusca (Hinds). However, interactions between F. fusca and P. ananatis as well as transmission mechanisms largely remain uncharacterized. This study investigated P. ananatis acquisition by thrips and transstadial persistence. Furthermore, the effects of bacterial acquisition on thrips fitness were also evaluated. When thrips larvae and adults were provided with acquisition access periods (AAP) on peanut leaflets contaminated with the bacterium, an exponentially positive relationship was observed between AAP and P. ananatis acquisition (R(2) ≥ 0.77, P = 0.01). P. ananatis persisted in thrips through several life stages (larvae, pupae, and adult). Despite the bacterial persistence, no significant effects on thrips fitness parameters such as fecundity and development were observed. Immunofluorescence microscopy of adult thrips with P. ananatis-specific antibody after 48 h AAP on contaminated food revealed that the bacterium was localized only in the gut. These results suggested that the pathogen is not circulative and could be transmitted through feces. Mechanical inoculation of onion seedlings with fecal rinsates produced center rot symptoms, whereas inoculation with rinsates potentially containing salivary secretions did not. These results provide evidence for stercorarian transmission (transmission through feces) of P. ananatis by F. fusca.
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The Tomato spotted wilt virus genome is processed differentially in its plant host Arachis hypogaea and its thrips vector Frankliniella fusca
Frontiers Media S.A., 2016Co-Authors: Rajagopalbabu Srinivasan, Anita Shrestha, Stephen John Fletcher, Jonathan Peters, Bernard J Carroll, Hanu R Pappu, Neena MitterAbstract:Thrips-transmitted tospoviruses are economically important viruses affecting a wide range of field and horticultural crops worldwide. Tomato spotted wilt virus is the type member of the Tospovirus genus with a broad host range of more than 900 plant species. Interactions between these viruses and their plant hosts and insect vectors via RNA interference pathways are likely a key determinant of pathogenicity. The current investigation, for the first time, compares biogenesis of small RNAs between the plant host and insect vector in the presence or absence of TSWV. Unique viral small interfering RNA (vsiRNA) profiles are evident for Arachis hypogaea (peanut) and Frankliniella fusca (thrips vector) following infection with TSWV. Differences between vsiRNA profiles for these plant and insect species, such as the relative abundance of 21 nt and 22 nt vsiRNAs and locations of alignment hotspots, reflect the diverse siRNA biosynthesis pathways of their respective kingdoms. The presence of unique vsiRNAs in F. fusca samples indicates that vsiRNA generation takes place within the thrips, and not solely through uptake via feeding on vsiRNAs produced in infected A. hypogaea. The study also shows key vsiRNA profile differences for TSWV among plant families, which are evident in the case of A. hypogaea, a legume, and members of Solanaceae (S. lycopersicum and N. benthamiana). Distinctively, overall small RNA biogenesis in A. hypogaea is markedly affected with an absence of the 24 nt small RNAs in TSWV-infected plants, possibly leading to wide-spread molecular and phenotypic perturbations specific to this species. These findings add significant information on the host-virus-vector interaction in terms of RNAi pathways and may lead to better crop and vector specific control strategies
R D Gitaitis - One of the best experts on this subject based on the ideXlab platform.
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interactions between Frankliniella fusca and pantoea ananatis in the center rot epidemic of onion allium cepa
Phytopathology, 2016Co-Authors: Bhabesh Dutta, Apurba K Barman, Utku Avci, R D Gitaitis, Kathleen Marasigan, Rajagopalbabu SrinivasanAbstract:An Enterobacteriaceae bacterium, Pantoea ananatis (Serrano) Mergaert, is the causal agent of an economically important disease of onion, center rot. P. ananatis is transmitted by an onion-infesting thrips, Frankliniella fusca (Hinds). However, interactions between F. fusca and P. ananatis as well as transmission mechanisms largely remain uncharacterized. This study investigated P. ananatis acquisition by thrips and transstadial persistence. Furthermore, the effects of bacterial acquisition on thrips fitness were also evaluated. When thrips larvae and adults were provided with acquisition access periods (AAP) on peanut leaflets contaminated with the bacterium, an exponentially positive relationship was observed between AAP and P. ananatis acquisition (R(2) ≥ 0.77, P = 0.01). P. ananatis persisted in thrips through several life stages (larvae, pupae, and adult). Despite the bacterial persistence, no significant effects on thrips fitness parameters such as fecundity and development were observed. Immunofluorescence microscopy of adult thrips with P. ananatis-specific antibody after 48 h AAP on contaminated food revealed that the bacterium was localized only in the gut. These results suggested that the pathogen is not circulative and could be transmitted through feces. Mechanical inoculation of onion seedlings with fecal rinsates produced center rot symptoms, whereas inoculation with rinsates potentially containing salivary secretions did not. These results provide evidence for stercorarian transmission (transmission through feces) of P. ananatis by F. fusca.
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transmission of pantoea ananatis and p agglomerans causal agents of center rot of onion allium cepa by onion thrips thrips tabaci through feces
Phytopathology, 2014Co-Authors: Bhabesh Dutta, Apurba K Barman, Rajagopalbabu Srinivasan, Utku Avci, D E Ullman, David B Langston, R D GitaitisAbstract:Frankliniella fusca, the tobacco thrips, has been shown to acquire and transmit Pantoea ananatis, one of the causal agents of the center rot of onion. Although Thrips tabaci, the onion thrips, is a common pest of onions, its role as a vector of P. ananatis has been unknown. The bacterium, P. agglomerans, is also associated with the center rot of onion, but its transmission by thrips has not been previously investigated. In this study, we investigated the relationship of T. tabaci with P. ananatis and P. agglomerans. Surface-sterilized T. tabaci were provided with various acquisition access periods (AAP) on onion leaves inoculated with either P. ananatis or P. agglomerans. A positive exponential relationship was observed between thrips AAP duration and P. ananatis (R² = 0.967; P = 0.023) or P. agglomerans acquisition (R² = 0.958; P = 0.017). Transmission experiments conducted with T. tabaci adults indicated that 70% of the seedlings developed center rot symptoms 15 days after inoculation. Immunofluorescence microscopy with antibodies specific to P. ananatis revealed that the bacterium was localized only in the gut of T. tabaci adults. Mechanical inoculation of onion seedlings with fecal rinsates alone produced center rot but not with salivary secretions. Together these results suggested that T. tabaci could efficiently transmit P. ananatis and P. agglomerans.
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transmission of iris yellow spot virus by Frankliniella fusca and thrips tabaci thysanoptera thripidae
Journal of Economic Entomology, 2012Co-Authors: Rajagopalbabu Srinivasan, David G. Riley, Sivamani Sundaraj, H R Pappu, Stan Diffie, R D GitaitisAbstract:Thrips-transmitted Iris yellow spot virus (IYSV) (Family Bunyaviridae, Genus Tospovirus) affects onion production in the United States and worldwide. The presence of IYSV in Georgia was confirmed in 2003. Two important thrips species that transmit tospoviruses, the onion thrips (Thrips tabaci (Lindeman)) and the tobacco thrips (Frankliniella fusca (Hinds)) are known to infest onion in Georgia. However, T. tabaci is the only confirmed vector of IYSV. Experiments were conducted to test the vector status of F. fusca in comparison with T. tabaci. F. fusca and T. tabaci larvae and adults reared on IYSV-infected hosts were tested with antiserum specific to the nonstructural protein of IYSV through an antigen coated plate ELISA. The detection rates for F. fusca larvae and adults were 4.5 and 5.1%, respectively, and for T. tabaci larvae and adults they were 20.0 and 24.0%, respectively, indicating that both F. fusca and T. tabaci can transmit IYSV. Further, transmission efficiencies of F. fusca and T. tabaci were evaluated by using an indicator host, lisianthus (Eustoma russellianum (Salisbury)). Both F. fusca and T. tabaci transmitted IYSV at 18.3 and 76.6%, respectively. Results confirmed that F. fusca also can transmit IYSV but at a lower efficiency than T. tabaci. To attest if low vector competency of our laboratory-reared F. fusca population affected its IYSV transmission capability, a Tomato spotted wilt virus (Family Bunyaviridae, Genus Tospovirus) transmission experiment was conducted. F. fusca transmitted Tomato spotted wilt virus at a competent rate (90%) suggesting that the transmission efficiency of a competent thrips vector can widely vary between two closely related viruses.
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first report of vidalia onion allium cepa naturally infected with tomato spotted wilt virus and iris yellow spot virus family bunyaviridae genus tospovirus in georgia
Plant Disease, 2004Co-Authors: S W Mullis, David B Langston, David G. Riley, R D Gitaitis, Alton N Sparks, J L Sherwood, A C Csinos, Reid L Torrance, M J CookAbstract:Vidalia onion is an important crop in Georgia's agriculture with worldwide recognition as a specialty vegetable. Vidalia onions are shortday, Granex-type sweet onions grown within a specific area of southeastern Georgia. Tomato spotted wilt virus (TSWV) has been endemic to Georgia crops for the past decade, but has gone undetected in Vidalia onions. Tobacco thrips (Frankliniella fusca) and Western flower thrips (Frankliniella occidentalis) are the primary vectors for TSWV in this region, and a number of plant species serve as reproductive reservoirs for the vector or virus. Iris yellow spot virus (IYSV), an emerging tospovirus that is potentially a devastating pathogen of onion, has been reported in many locations in the western United States (2,4). Thrips tabaci is the known vector for IYSV, but it is unknown if noncrop plants play a role in its epidemiology in Georgia. During October 2003, a small (n = 12) sampling of onions with chlorosis and dieback of unknown etiology from the Vidalia region was screened for a variety of viruses, and TSWV and IYSV infections were serologically detected. Since that time, leaf and bulb tissues from 4,424 onion samples were screened for TSWV and IYSV using double antibody sandwich-enzyme linked immunosorbent assay (DAS-ELISA) with commercial kits (Agdia Inc., Elkhart, IN). Samples were collected from 53 locations in the Vidalia region during the growing season between November 2003 and March 2004. Plants exhibiting stress, such as tip dieback, necrotic lesions, chlorosis or environmental damage were selected. Of these, 306 were positive for TSWV and 396 were positive for IYSV using positive threshold absorbance of three times the average plus two standard deviations of healthy negative onion controls. Positive serological findings of the onion tissues were verified by immunocapture-reverse transcription-polymerase chain reaction (IC-RT-PCR) for TSWV (3) and RT-PCR for IYSV (1). In both instances, a region of the viral nucleocapsid (N) gene was amplified. The PCR products were analyzed with gel electrophoresis with an ethidium bromide stain in 0.8% agarose. Eighty-six percent (n = 263) of the TSWV ELISA-positive samples exhibited the expected 774-bp product and 55 percent (n = 217) of the IYSV ELISA-positive samples exhibited the expected 962-bp product. The reduced success of the IYSV verification could be attributed to the age and deteriorated condition of the samples at the time of amplification. Thrips tabaci were obtained from onion seedbeds and cull piles within the early sampling (n = 84) and screened for TSWV by the use of an indirect-ELISA to the nonstructural (NSs) protein of TSWV. Of the thrips sampled, 25 were positive in ELISA. While the incidence of IYSV and TSWV in the Vidalia onion crop has been documented, more research is needed to illuminate their potential danger to Vidalia onions. References: (1) I. Cortes et al. Phytopathology 88:1276, 1998. (2) L. J. du Toit et al. Plant Dis. 88:222, 2004. (3) R. K. Jain et al. Plant Dis. 82:900, 1998. (4) J. W. Moyer et al. (Abstr.) Phytopathology 93(suppl.):S115, 2003.
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transmission of pantoea ananatis causal agent of center rot of onion by tobacco thrips Frankliniella fusca
Plant Disease, 2003Co-Authors: R D Gitaitis, M L Wells, R R Walcott, J Diaz C Perez, F H SandersAbstract:Center rot of onion, caused by Pantoea ananatis, was first reported on onion in Georgia in 1997 and has continued to reduce yields and cause postharvest losses. In a previous study, we developed a nondestructive assay that demonstrated an association between P. ananatis and approximately 10% of the tobacco thrips, Frankliniella fusca, surveyed. In this study, we report that all strains of P. ananatis, isolated from surface-sterilized, crushed thrips, were pathogenic when inoculated onto greenhouse-grown onion plants. Furthermore, when 6 to 12 thrips harboring populations of P. ananatis of 1 × 103 CFU ml-1 or greater were placed on healthy onion seedlings to feed, disease transmission occurred in 52% of the plants challenged. Incubation periods ranged from 4 to 9 days. Bacteria isolated from symptoms typical of those associated with center rot were characterized and identified as P. ananatis. In contrast, an equal number of plants remained healthy for up to 28 days after being exposed to the same number of tobacco thrips that were identified as being free of P. ananatis.
Russell L Groves - One of the best experts on this subject based on the ideXlab platform.
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the influence of temperature and precipitation on spring dispersal of Frankliniella fusca changes as the season progresses
Entomologia Experimentalis Et Applicata, 2010Co-Authors: Shannon C Morsello, Russell L Groves, Brian A Nault, Amanda L P Beaudoin, George G KennedyAbstract:Effects of temperature and precipitation on spring dispersal patterns of Frankliniella fusca (Hinds) (Thysanoptera: Thripidae) caught on yellow sticky traps were estimated in central and eastern North Carolina and eastern Virginia, USA, from 1997 to 2001, and in 2004 and 2007. Data were collected from 44 sites within 14 locations over 7 years, resulting in 30 location-year data combinations. The following independent variables were examined to determine their relationship to the number of F. fusca caught on sticky traps during specified time intervals: cumulative degree days (base 10.5 � C) from 1 November to the start of each trapping interval (DD), number of days with temperatures favorable for flight during each trapping interval (DTFF), and an index of rainfall during specific intervals prior to and during the trapping interval (RI). Regression models that contained various combinations of these variables explained 62, 79, 74, and 68% of the variation in the number of dispersing F. fusca captured during 1‐15 April, 16‐30 April, 1‐15 May, and 16‐31 May, respectively. The results provide strong evidence that the suppressive effects of precipitation on growth of local populationsdevelopingduringlatewinterandearlyspringaresubsequentlymanifestatthelandscape scale as reductions in the populations of dispersing adults that may persist for as long as 5‐6 weeks after the precipitation occurs.
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temperature and precipitation affect seasonal patterns of dispersing tobacco thrips Frankliniella fusca and onion thrips thrips tabaci thysanoptera thripidae caught on sticky traps
Environmental Entomology, 2008Co-Authors: Shannon C Morsello, Russell L Groves, Brian A Nault, George G KennedyAbstract:Effects of temperature and precipitation on the temporal patterns of dispersing tobacco thrips, Frankliniella fusca, and onion thrips, Thrips tabaci, caught on yellow sticky traps were estimated in central and eastern North Carolina and eastern Virginia from 1997 through 2001. The impact that these environmental factors had on numbers of F. fusca and T. tabaci caught on sticky traps during April and May was determined using stepwise regression analysis of 43 and 38 site-years of aerial trapping data from 21 and 18 different field locations, respectively. The independent variables used in the regression models included degree-days, total precipitation, and the number of days in which precipitation occurred during January through May. Each variable was significant in explaining variation for both thrips species and, in all models, degree-days was the single best explanatory variable. Precipitation had a comparatively greater effect on T. tabaci than F. fusca. The numbers of F. fusca and T. tabaci captured in flight were positively related to degree-days and the number of days with precipitation but negatively related to total precipitation. Combined in a single model, degree-days, total precipitation, and the number of days with precipitation explained 70 and 55% of the total variation in the number of F. fusca captured from 1 April through 10 May and from 1 April through 31 May, respectively. Regarding T. tabaci flights, degree-days, total precipitation, and the number of days with precipitation collectively explained 57 and 63% of the total variation in the number captured from 1 April through 10 May and from 1 April through 31 May, respectively.
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seasonal dispersal patterns of Frankliniella fusca thysanoptera thripidae and tomato spotted wilt virus occurrence in central and eastern north carolina
Journal of Economic Entomology, 2003Co-Authors: Russell L Groves, J W Moyer, James F. Walgenbach, George G KennedyAbstract:The seasonal abundance and temporal pattern of Frankliniella fusca Hinds dispersal were monitored from 1996 to 2000 at 12 locations in central and eastern North Carolina. The predominant vector species of tomato spotted wilt virus (TSWV) captured across all locations was F. fusca (98%). The temporal patterns of F. fusca dispersal observed during spring seasons varied among locations in all years except 2000. Regression analysis estimated that times of first flight in the spring seasons varied among locations, whereas flight duration intervals were similar. Temporal patterns of F. fusca captured varied significantly between aerial traps placed 0.1 and 1.0 m above the soil surface. Fewer total thrips were captured at 0.1 m, although thrips dispersal occurred earlier and over a greater time interval compared with 1.0-m traps. Temporal patterns of TSWV occurrence differed among locations in the spring seasons of 1999 and 2000, whereas patterns of virus occurrence were similar during the fall seasons. Patterns of F. fusca dispersal and subsequent TSWV occurrence were synchronous at locations in 1999 and 2000 where the greatest number of TSWV lesions was recorded. Knowledge of the temporal patterns of F. fusca dispersal and TSWV occurrence may be a useful indicator for describing the time when susceptible crops are at highest risk of TSWV infection.
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the role of weed hosts and tobacco thrips Frankliniella fusca in the epidemiology of tomato spotted wilt virus
Plant Disease, 2002Co-Authors: Russell L Groves, J W Moyer, James F. Walgenbach, George G KennedyAbstract:Groves, R. L., Walgenbach, J. F., Moyer, J. W., and Kennedy, G. G. 2002. The role of weed hosts and tobacco thrips, Frankliniella fusca, in the epidemiology of Tomato spotted wilt virus. Plant Dis. 86:573-582. Wild plant species were systematically sampled to characterize reproduction of thrips, the vector of Tomato spotted wilt virus (TSWV), and natural sources TSWV infection. Thrips populations were monitored on 28 common perennial, biennial, and annual plant species over two noncrop seasons at six field locations across North Carolina. Sonchus asper, Stellaria media, and Taraxacum officianale consistently supported the largest populations of immature TSWV vector species. The tobacco thrips, Frankliniella fusca, was the most abundant TSWV vector species collected, comprising over 95% of vector species in each survey season. Perennial plant species (i.e., Plantago rugelii and Taraxacum officianale) were often only locally abundant, and many annual species (Cerastium vulgatum, Sonchus asper, and Stellaria media) were more widely distributed. Perennial species, including P. rugelii and Rumex crispus, remained TSWV infected for 2 years in a small-plot field test. Where these perennial species are locally abundant, they may serve as important and long-lasting TSWV inoculum sources. In random surveys across 12 locations in North Carolina, TSWV infection was documented by double antibody sandwich enzyme-linked immunosorbent assay in 35 of 72 (49%) common perennial (N = 10), biennial (N = 4), and annual (N = 21) plant species across 18 plant families. Estimated rates of TSWV infection were highest in Cerastium vulgatum (4.2%), Lactuca scariola (1.3%), Molluga verticillata (4.3%), Plantago rugelii (3.4%), Ranunculus sardous (3.6%), Sonchus asper (5.1%), Stellaria media (1.4%), and Taraxacum officianale (5.8%). Nine plant species were determined to be new host recordings for TSWV infection, including Cardamine hirsuta, Eupatorium capillifolium, Geranium carolinianum, Gnaphalium purpureum, Linaria canadense, Molluga verticillata, Pyrrhopappus carolinianus, Raphanus raphanistrum, and Triodanis perfoliata. Our findings document the relative potential of a number of common annual, biennial, and perennial plant species to act as important reproductive sites for F. fusca and as acquisition sources of TSWV for spread to susceptible crops. Additional keywords: Frankliniella occidentalis, Thrips tabaci
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The Role of Weed Hosts and Tobacco Thrips, Frankliniella fusca, in the Epidemiology of Tomato spotted wilt virus.
Plant disease, 2002Co-Authors: Russell L Groves, J W Moyer, James F. Walgenbach, George G KennedyAbstract:Wild plant species were systematically sampled to characterize reproduction of thrips, the vector of Tomato spotted wilt virus (TSWV), and natural sources TSWV infection. Thrips populations were monitored on 28 common perennial, biennial, and annual plant species over two noncrop seasons at six field locations across North Carolina. Sonchus asper, Stellaria media, and Taraxacum officianale consistently supported the largest populations of immature TSWV vector species. The tobacco thrips, Frankliniella fusca, was the most abundant TSWV vector species collected, comprising over 95% of vector species in each survey season. Perennial plant species (i.e., Plantago rugelii and Taraxacum officianale) were often only locally abundant, and many annual species (Cerastium vulgatum, Sonchus asper, and Stellaria media) were more widely distributed. Perennial species, including P. rugelii and Rumex crispus, remained TSWV infected for 2 years in a small-plot field test. Where these perennial species are locally abundant, they may serve as important and long-lasting TSWV inoculum sources. In random surveys across 12 locations in North Carolina, TSWV infection was documented by double antibody sandwich enzyme-linked immunosorbent assay in 35 of 72 (49%) common perennial (N = 10), biennial (N = 4), and annual (N = 21) plant species across 18 plant families. Estimated rates of TSWV infection were highest in Cerastium vulgatum (4.2%), Lactuca scariola (1.3%), Molluga verticillata (4.3%), Plantago rugelii (3.4%), Ranunculus sardous (3.6%), Sonchus asper (5.1%), Stellaria media (1.4%), and Taraxacum officianale (5.8%). Nine plant species were determined to be new host recordings for TSWV infection, including Cardamine hirsuta, Eupatorium capillifolium, Geranium carolinianum, Gnaphalium purpureum, Linaria canadense, Molluga verticillata, Pyrrhopappus carolinianus, Raphanus raphanistrum, and Triodanis perfoliata. Our findings document the relative potential of a number of common annual, biennial, and perennial plant species to act as important reproductive sites for F. fusca and as acquisition sources of TSWV for spread to susceptible crops.
