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16 results on '"Dreaden, T J"'

4. No rest for the laurels: symbiotic invaders cause unprecedented damage to southern USA forests

Author

Hughes, M, Riggins, J, Koch, F H, Cognato, A I, Anderson, Claire, Formby, J P, Dreaden, T J, Ploetz, R C, Smith, J A, Hughes, M, Riggins, J, Koch, F H, Cognato, A I, Anderson, Claire, Formby, J P, Dreaden, T J, Ploetz, R C, and Smith, J A

Abstract

Laurel wilt is an extraordinarily destructive exotic tree disease in the southeastern United States that involves new-encounter hosts in the Lauraceae, an introduced vector (Xyleborus glabratus) and pathogen symbiont (Raffaelea lauricola). USDA Forest Service Forest Inventory and Analysis data were used to estimate that over 300 million trees of redbay (Persea borbonia sensu lato) have succumbed to the disease since the early 2000s (ca 1/3 of the pre-invasion population). In addition, numerous native shrub and tree species in the family are susceptible and threatened in the Western Hemisphere. Genetic markers were used to test the hypothesis that the vector and pathogen entered North America as a single introduction. With a portion of the cytochrome oxidase I gene, a single X. glabratus haplotype was detected in the USA. Similarly, Amplified Fragment Length Polymorphisms indicated that 95% (54 of 57) of the isolates of R. lauricola that were examined were of a single clonal genotype; only minor variation was detected in three polymorphic isolates. Similar levels of disease developed after swamp bay (P. palustris) was inoculated with each of the four genotypes of R. lauricola. It is proposed that a single founding event is responsible for the laurel wilt epidemic in the United States.

Published
2017

5. Recovery Plan for Laurel Wilt of Avocado, Caused by Raffaelea lauricola

Author

Ploetz, R. C., primary, Hughes, M. A., additional, Kendra, P. E., additional, Fraedrich, S. W., additional, Carrillo, D., additional, Stelinski, L. L., additional, Hulcr, J., additional, Mayfield, A. E., additional, Dreaden, T. J., additional, Crane, J. H., additional, Evans, E. A., additional, Schaffer, B. A., additional, and Rollins, J. A., additional

Published
2017
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8. Response of swamp bay, Persea palustris, and redbay, P. borbonia, to Raffaelea spp. isolated from Xyleborus glabratus.

Author

Dreaden, T. J., Campbell, A. S., Gonzalez‐Benecke, C. A., Ploetz, R. C., Smith, J. A., and Klopfenstein, N. B.

Subjects
*LAUREL, *LAURACEAE, *PLANT species, *PLANT diseases, *PATHOGENIC microorganisms
Abstract

Laurel wilt is a devastating invasive disease of members of the Lauraceae plant family. It is caused by the fungus Raffaelea lauricola, which is a nutritional symbiont of its ambrosia beetle vector, Xyleborus glabratus. In the United States, six Raffaelea spp., in addition to R. lauricola, have been recovered from mycangia of X. glabratus. We compared the response of two laurel wilt suspects, swamp bay ( Persea palustris) and redbay ( Persea borbonia), to five of these species, another undescribed Raffaelea sp., and R. lauricola. Six weeks after inoculation, only R. lauricola caused significantly greater symptoms than water inoculations. The fungi varied in their ability to move systemically and be recovered from the host at the end of the experiment. Stem hydraulic conductivity was decreased by R. lauricola, but none of the other taxa. Although the roles these fungi play in the life cycle of X. glabratus are not known, they do not appear to be pathogens on these host tree species. [ABSTRACT FROM AUTHOR]

Published
2017
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16. Development and evaluation of a real-time PCR seed lot screening method for Fusarium circinatum, causal agent of pitch canker disease.

Author

Dreaden, T. J., Smith, J. A., Barnard, E. L., and Blakeslee, G.

Subjects
*POLYMERASE chain reaction, *FUSARIUM, *CANKER (Plant disease), *PITCH pine, *SEED screenings, *PATHOGENIC fungi
Abstract

Fusarium circinatum is a serious pathogen of Pinus spp. worldwide, causing pitch canker disease. F. circinatum can contaminate seeds both internally and externally and is readily disseminated via contaminated seed. Many countries require screening of pine seeds for F. circinatum before they can be imported. The currently accepted screening method is based on culturing the pathogen on a semi-selective medium and identifying it using morphological traits. This method is time-consuming and does not allow for accurate identification of the pathogen to the species level. A bulk DNA extraction and real-time PCR procedure to screen seeds for the presence of F. circinatum were developed in this study. The real-time PCR method resulted in the detection of F. circinatum in 5 of 6 commercial seed lots tested and has a lower detection limit of 1 × 10−5 ng of F. circinatum DNA per PCR. The culture-based method detected Fusarium spp. in four of six of the same seed lots. The real-time PCR method can be used to screen multiple seed lots in 2 days, whereas the culture-based method requires a minimum of 1-2 weeks. This new real-time PCR seed screening method allows for fast, sensitive and accurate screening and can be adapted to handle larger volumes of seeds. [ABSTRACT FROM AUTHOR]

Published
2012
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