Skip to Main Content
 

Global Search Box

 
 
 
 

Files

File List


Lin_Dissertation_final.pdf (5.1 MB)

ETD Abstract Container

Abstract Header

Etiology, Epidemiology and Management of Fruit Rot of Deciduous Holly in U.S. Nursery Production

Lin, Shan
http://rave.ohiolink.edu/etdc/view?acc_num=osu1543239267181558

Abstract Details

2018, Doctor of Philosophy, Ohio State University, Plant Pathology.
Cut branches of deciduous holly (Ilex spp.) carrying shiny and colorful fruit are popularly used for holiday decorations in the United States. Since 2012, an emerging disease causing the fruit to rot was observed across Midwestern and Eastern U.S. nurseries. A variety of other symptoms were associated with the disease, including undersized, shriveled, and dull fruit, as well as leaf spots and early plant defoliation. The disease causal agents were identified by laboratory processing of symptomatic fruit collected from nine locations across four states over five years by means of morphological characterization, multi-locus phylogenetic analyses and pathogenicity assays. Alternaria alternata and a newly described species, Diaporthe ilicicola sp. nov., were identified as the primary pathogens associated with the disease, and A. arborescens, Colletotrichum fioriniae, C. nymphaeae, Epicoccum nigrum and species in the D. eres species complex were identified as minor pathogens in this disease complex. To determine the sources of pathogen inoculum in holly fields, and the growth stages of host susceptibility to fungal infections, we monitored the presence of these pathogens in different plant tissues (i.e., dormant twigs, mummified fruit, leaves and fruit), and we studied inoculum dynamics and assessed disease progression throughout the growing season in three Ohio nurseries exposed to natural inoculum over two consecutive years. Additionally, an outdoor container trial was conducted by artificially inoculating plant tissues using individual or combined pathogen inoculum at different stages of plant development (i.e., flower bud, full bloom, petal fall, immature fruit and mature fruit). In nursery conditions, fruit rot pathogens were consistently isolated from all types of plant tissues analyzed. Mummified fruit and bark were found to be the main sources of primary inoculum, while leaf spots were identified as a source of secondary inoculum for fruit infections. Alternaria and Colletotrichum had significantly higher isolation frequency after bloom, and peak inoculum capture by spore traps was observed during bloom. In the container trial, Diaporthe ilicicola inoculations during bloom and petal fall stages resulted in latent infections with symptoms developing when fruit reached maturity. In addition, all pathogens successfully infected mature wounded fruit. These results indicate that bloom is a critical stage to manage fruit infections and that implementing practices for fruit injury protection may lower disease levels in the field. This research represent the first step to understand this emerging fruit rot on deciduous holly and to build a foundation for further investigations. Further studies should be conducted to fully understand the effects of environmental parameters on seasonal inoculum dynamics and of host physiological factors contributing to disease development.
Francesca Peduto Hand (Advisor)
Anne Dorrance (Committee Member)
Laurence Madden (Committee Member)
Sally Miller (Committee Member)
Plant Pathology

Recommended Citations

Citations

  • Lin, S. (2018). Etiology, Epidemiology and Management of Fruit Rot of Deciduous Holly in U.S. Nursery Production [Doctoral dissertation, Ohio State University]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=osu1543239267181558

    APA Style (7th edition)

  • Lin, Shan. Etiology, Epidemiology and Management of Fruit Rot of Deciduous Holly in U.S. Nursery Production. 2018. Ohio State University, Doctoral dissertation. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=osu1543239267181558.

    MLA Style (8th edition)

  • Lin, Shan. "Etiology, Epidemiology and Management of Fruit Rot of Deciduous Holly in U.S. Nursery Production." Doctoral dissertation, Ohio State University, 2018. http://rave.ohiolink.edu/etdc/view?acc_num=osu1543239267181558

    Chicago Manual of Style (17th edition)

osu1543239267181558
343
© 2018, all rights reserved.
This open access ETD is published by The Ohio State University and OhioLINK.