Fort Pierce, FL, United States
Fort Pierce, FL, United States

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Kumar V.,Tropical Research and Education Center | Seal D.R.,Tropical Research and Education Center | Schuster D.J.,Gulf Coast Research and Education Center | McKenzie C.,Us Horticultural Research Laboratory | And 3 more authors.
Florida Entomologist | Year: 2011

The chilli thrips, Scirtothrips dorsalis Hood (Thysanoptera: Thripidae) is an emerging pest of many economically important vegetable and ornamental crops grown in the United States. Accurate identification of this pest is a fundamental requirement in development of effective quarantine and management strategies. Using scanning electron microscopy, high resolution images of important taxonomic traits of this pest were produced, which will aid research, regulatory and extension personnel to identify this pest. High resolution images were obtained for identifying characters of S. dorsalis including tergites with antecostal ridges; head with 3 pairs of ocellar setae, metanotum presenting longitudinal striations with medially located pair of setae; veins of forewing presenting widely spaced setae; segment VIII with complete posteromarginal comb of microtrichia; and sternites lacking discal setae but covered with rows of microtrichia except in the antero-medial region. Further, a preliminary comparison of morphological traits of S. dorsalis populations from different geographical regions was conducted, which can help in understanding the phenotype of this pest. Specimens of S. dorsalis were obtained from 5 distinct geographical regions: New Delhi, India; Shizouka, Japan; Negev, Israel; St. Vincent and Florida in the United States. Fourteen morphological characters of each population of S. dorsalis were measured and compared among the 5 populations. No significant differences were observed between the body lengths of the various S. dorsalis populations, which ranged from 0.85 mm (Negev) to 0.98 mm (Florida). When comparing 12 morphological characters, we found no significant differences among New Delhi, St. Vincent, Negev and Florida populations. However, when S. dorsalis populations of these 4 regions were compared with Shizouka, significant differences were detected for either 2 or 5 morphological characters depending on the population, suggesting the Japan population is more robust i.e., longer and wider mesothorax and metathorax, and wider abdomens. Also, the mean lengths of body size among different populations did not vary directly or inversely with latitude.


Dickey A.M.,University of Florida | Dickey A.M.,Us Horticultural Research Laboratory | Dickey A.M.,U.S. Department of Agriculture | Kumar V.,University of Florida | And 12 more authors.
PLoS ONE | Year: 2015

Invasive arthropods pose unique management challenges in various environments, the first of which is correct identification. This apparently mundane task is particularly difficult if multiple species are morphologically indistinguishable but accurate identification can be determined with DNA barcoding provided an adequate reference set is available. Scirtothrips dorsalis is a highly polyphagous plant pest with a rapidly expanding global distribution and this species, as currently recognized, may be comprised of cryptic species. Here we report the development of a comprehensive DNA barcode library for S. dorsalis and seven nuclear markers via next-generation sequencing for identification use within the complex. We also report the delimitation of nine cryptic species and two morphologically distinguishable species comprising the S. dorsalis species complex using histogram analysis of DNA barcodes, Bayesian phylogenetics, and the multi-species coalescent. One member of the complex, here designated the South Asia 1 cryptic species, is highly invasive, polyphagous, and likely the species implicated in tospovirus transmission. Two other species, South Asia 2, and East Asia 1 are also highly polyphagous and appear to be at an earlier stage of global invasion. The remaining members of the complex are regionally endemic, varying in their pest status and degree of polyphagy. In addition to patterns of invasion and endemism, our results provide a framework both for identifying members of the complex based on their DNA barcode, and for future species delimiting efforts.


Bar-Joseph M.,GimlaoTec | Robertson C.,University of Florida | Hilf M.E.,Us Horticultural Research Laboratory | Dawson W.O.,University of Florida
Journal of Horticultural Science and Biotechnology | Year: 2011

We have developed a novel technique for grafting citrus seeds onto citrus rootstock plants that resulted in successful graft-take with normal vascular connections between the emerging seedling stem tissues and the rootstock plant.The method was found to be suitable for producing grafted plants from seeds of six cultivars and hybrids of Citrus and the citrus relative Murraya paniculata, using four common Citrus rootstocks. Plants produced by this method developed normally and were established in the field more rapidly than those produced by the common practice of grafting the rootstocks with budwood derived from seedlings prepared from seed in soil-based media. Seed grafting is expected to find a range of uses in breeding programmes; for example, by reducing the time required for the evaluation of hybrid seedlings, in cases where the female parent is mono-embryonic, for testing for vertical transmission of pathogens, and for screening for pathogen resistance among hybrid and mutagenised seed sources.


Wilson P.C.,University of Florida | Riiska C.,University of Florida | Albano J.P.,Us Horticultural Research Laboratory
Journal of Environmental Quality | Year: 2010

Commercial foliage plant production requires the use of pesticides for controlling pests and pathogens that can reduce aesthetic qualities of crops, rendering them unwanted by consumers. Chlorothalonil is a common, broad-spectrum, foliar fungicide used for protecting plants from a variety of fungal diseases. This fungicide may also be acutely toxic to nontarget aquatic organisms due to its mode of action. This study evaluated the amount of chlorothalonil deposited on nontarget ground surfaces during normal sprayer applications at a commercial nursery using Teflon targets. One day following application, irrigation runoff events were initiated and runoff water samples were collected and analyzed for chlorothalonil. Discharge volumes were also measured to allow estimation of the total mass of chlorothalonil discharged during each event. Results indicated that 9.8 to 53.6% of the active ingredient applied landed on nontarget ground surfaces depending on plant size, spacing, and row lengths (short rows sprayed from one side vs. longer rows sprayed from boThends). On an entire production-area scale, 29.2% of the active ingredient applied was deposited on ground surfaces. Of the total nontarget deposition, 0.25 to 0.53% was detected in runoff water discharged from the production area. Concentrations ranged from 1.2 to 500 μg/L during the first runoff events following application. Copyright © 2010 by the American Society of Agronomy.


Kumar V.,University of Florida | Seal D.R.,University of Florida | Kakkar G.,University of Florida | McKenzie C.L.,Us Horticultural Research Laboratory | Osborne L.S.,Mid Florida Research and Education Center
Florida Entomologist | Year: 2012

During scouting and sampling various of plant species at different commercial nurseries in Miami- Dade County, Florida, 12 different crops were found to be economically affected by S. dorsalis in a commercial nursery. An open free choice host susceptibility test was conducted on 6 fruit hosts from the nursery. Canistel, mango, sapodilla and miracle fruit were found to be most affected among the fruit hosts with maximum damage ratings of 2.78, 2.67, 1.67 and 0.77 respectively. Since the host range of this pest is expanding, a careful monitoring and sampling protocols, especially of potted plants, should be diligently implemented to prevent and retard its distribution in different regions.


Dickey A.M.,Us Horticultural Research Laboratory | Dickey A.M.,University of Florida | Dickey A.M.,U.S. Department of Agriculture | Kumar V.,Us Horticultural Research Laboratory | And 8 more authors.
BMC Genomics | Year: 2015

Background: Multipartite mitochondrial genomes are very rare in animals but have been found previously in two insect orders with highly rearranged genomes, the Phthiraptera (parasitic lice), and the Psocoptera (booklice/barklice). Results: We provide the first report of a multipartite mitochondrial genome architecture in a third order with highly rearranged genomes: Thysanoptera (thrips). We sequenced the complete mitochondrial genomes of two divergent members of the Scirtothrips dorsalis cryptic species complex. The East Asia 1 species has the single circular chromosome common to animals while the South Asia 1 species has a genome consisting of two circular chromosomes. The fragmented South Asia 1 genome exhibits extreme chromosome size asymmetry with the majority of genes on the large, 14.28 kb, chromosome and only nad6 and trnC on the 0.92 kb mini-circle chromosome. This genome also features paralogous control regions with high similarity suggesting a very recent origin of the nad6 mini-circle chromosome in the South Asia 1 cryptic species. Conclusions: Thysanoptera, along with the other minor paraenopteran insect orders should be considered models for rapid mitochondrial genome evolution, including fragmentation. Continued use of these models will facilitate a greater understanding of recombination and other mitochondrial genome evolutionary processes across eukaryotes. © 2015 Dickey et al.


Diaz R.,University of Florida | Aguirre C.,University of Florida | Wheeler G.S.,USDAARS Invasive Plant Research Laboratory | Lapointe S.L.,Us Horticultural Research Laboratory | And 2 more authors.
Environmental Entomology | Year: 2011

The leaf feeding beetle Gratiana boliviana Spaeth has been released since 2003 in the southeastern United States for biological control of tropical soda apple, Solanum viarum Dunal. In Florida, G. boliviana can be found on tropical soda apple growing in open pastures as well as in shady wooded areas. The objectives of this study were to determine the effect of light intensity on the performance of tropical soda apple and G. boliviana under greenhouse conditions, and to determine the abundance and mortality of G. boliviana in open and shaded habitats. Leaves growing in the shade were less tough, had higher water and nitrogen content, lower soluble sugars, and less dense and smaller glandular trichomes compared with leaves growing in the open. Plants grew slightly taller and wider under shaded conditions but total biomass was significantly reduced compared with plants grown in the open. In the greenhouse, G. boliviana had higher immature survival, greater folivory, larger adult size, and higher fecundity when reared on shaded plants compared with open plants. Sampling of field populations revealed that the overall abundance of G. boliviana was lower but leaf feeding damage was higher in shaded habitats compared with the open habitats. The percentage of eggs surviving to adult was greater in shaded compared with open habitats. The abundance of predators was higher in the open pasture and was positively correlated with the abundance of G. boliviana. These results indicate that not only plant quality but also habitat structure are important to the performance of weed biological control agents. © 2011 Entomological Society of America.


Boykin L.M.,Us Horticultural Research Laboratory | Boykin L.M.,Lincoln University at Christchurch | Shatters Jr. R.G.,Us Horticultural Research Laboratory | Hall D.G.,Us Horticultural Research Laboratory | And 2 more authors.
Journal of Economic Entomology | Year: 2010

Anastrepha suspensa (Loew) (Diptera: Tephritidae), the Caribbean fruit fly, is indigenous to Florida and the Greater Antilles where it causes economic losses in fruit crops, including citrus. Because of the geographic separation of many of its native locations and anecdotal descriptions of regional differences in host preferences, there have been questions about the population structure of A. suspensa. Seven DNA microsatellite markers were used to characterize the population genetic structure of A. suspensa, in Florida and the Caribbean from a variety of hosts, including citrus. We genotyped 729 A. suspensa individuals from Florida, Puerto Rico, Cayman Island, Dominican Republic, and Jamaica. The investigated seven loci displayed from 5 to 19 alleles, with expected heterozygosities ranging from 0.05 to 0.83. There were five unique alleles in Florida and three unique alleles in the Caribbean samples; however, no microsatellite alleles were specific to a single host plant. Genetic diversity was analyzed using FST and analysis of molecular variance and revealed low genetic diversity between Florida and Caribbean samples and also between citrus and noncitrus samples. Analyses using migrate revealed there is continuous gene flow between sampling sites in Florida and the Caribbean and among different hosts. These results support previous comparisons based on the mitochondrial cytochrome oxidase I locus indicating there is no genetic differentiation among locations in Florida and the Caribbean and that there is no separation into host races. © 2010 Entomological Society of America.


PubMed | Us Horticultural Research Laboratory
Type: Comparative Study | Journal: Journal of economic entomology | Year: 2011

Anastrepha suspensa (Loew) (Diptera: Tephritidae), the Caribbean fruit fly, is indigenous to Florida and the Greater Antilles where it causes economic losses in fruit crops, including citrus. Because of the geographic separation of many of its native locations and anecdotal descriptions of regional differences in host preferences, there have been questions about the population structure of A. suspensa. Seven DNA microsatellite markers were used to characterize the population genetic structure of A. suspensa, in Florida and the Caribbean from a variety of hosts, including citrus. We genotyped 729 A. suspensa individuals from Florida, Puerto Rico, Cayman Island, Dominican Republic, and Jamaica. The investigated seven loci displayed from 5 to 19 alleles, with expected heterozygosities ranging from 0.05 to 0.83. There were five unique alleles in Florida and three unique alleles in the Caribbean samples; however, no microsatellite alleles were specific to a single host plant. Genetic diversity was analyzed using F(ST) and analysis of molecular variance and revealed low genetic diversity between Florida and Caribbean samples and also between citrus and noncitrus samples. Analyses using migrate revealed there is continuous gene flow between sampling sites in Florida and the Caribbean and among different hosts. These results support previous comparisons based on the mitochondrial cytochrome oxidase I locus indicating there is no genetic differentiation among locations in Florida and the Caribbean and that there is no separation into host races.

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