Publications by authors named "N A Tisserat"

Article Synopsis
  • Diplodia shoot blight and canker disease (DSB) is caused by the fungal pathogen Diplodia sapinea and primarily affects 2-3 needled pines, such as ponderosa pine, resulting in various symptoms including necrotic needles, cankers, and dieback.
  • The pathogen can exist without visible symptoms in trees, making it difficult to detect, and outbreaks are more common in stressed environments like nurseries and seed orchards.
  • Although D. sapinea has not been previously reported in Colorado, studies confirmed its presence and pathogenicity after observing symptoms in ponderosa pines in Wyoming in 2018 and discovering symptomatic trees in Colorado in 2021.
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The focus of investigation in this study was to consider the potential of arthropods in the dissemination of the bacterium involved in drippy blight disease, . Arthropod specimens were collected and tested for the presence of the bacterium with molecular markers. The bacterium was confirmed on 12 different insect samples from three orders (Coleoptera, Hemiptera, and Hymenoptera) and eight families (Buprestidae, Coccinellidae, Dermestidae, Coreidae, Pentatomidae and/or Miridae, Apidae, Formicidae, and Vespidae).

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Fungi in the genus Geosmithia (Ascomycota: Hypocreales) are frequent associates of bark beetles and woodborers that colonize hardwood and coniferous trees. One species, Geosmithia morbida, is an economically damaging invasive species. The authors surveyed the Geosmithia species of California and Colorado, USA, to (i) provide baseline data on taxonomy of Geosmithia and beetle vector specificity across the western USA; (ii) investigate the subcortical beetle fauna for alternative vectors of the invasive G.

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Prevalence of Xanthomonas translucens, which causes cereal leaf streak (CLS) in cereal crops and bacterial wilt in forage and turfgrass species, has increased in many regions in recent years. Because the pathogen is seedborne in economically important cereals, it is a concern for international and interstate germplasm exchange and, thus, reliable and robust protocols for its detection in seed are needed. However, historical confusion surrounding the taxonomy within the species has complicated the development of accurate and reliable diagnostic tools for X.

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Geosmithia morbida is well documented as the causal agent of thousand cankers disease of black walnut trees. However, it is not well understood how G. morbida strains differ in virulence and how their interactions with co-occurring pathogens contribute to disease severity.

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