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Fort Pierce, FL, United States

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. Source

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. Source

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. Source

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. Source

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. Source

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