Author ORCID Identifier:

https://orcid.org/0009-0008-4202-957X

Date of Graduation

12-2025

Document Type

Thesis

Degree Name

Master of Science in Horticulture (MS)

Degree Level

Graduate

Department

Horticulture

Advisor/Mentor

Hutchens, Wendell

Committee Member

Richardson, Michael

Second Committee Member

Spurlock, Terry

Keywords

Bermudagrass; Plant Disease; Spring Dead Spot; Turfgrass

Abstract

Spring dead spot (SDS) is a destructive disease of bermudagrass (Cynodon Rich. spp.) in parts of the world that experience winter dormancy. Fungicides are often necessary to properly manage SDS, and significant research has been conducted to improve fungicidal effectiveness. Several studies were conducted with the objectives of improving fungicide application timing, method of fungicide application, and long-term fungicidal efficiency. In the fungicide application study, a cooling degree-day (CDD) model based on soil temperatures was developed. The CDD model showed that isofetamid was highly effective against SDS during a wide application window in autumn, while tebuconazole was inconsistently effective and must be applied during a narrow timing window. In a separate study to determine longevity of fungicide efficacy, out of several fungicides tested, only isofetamid provided multiple years of SDS suppression. Finally, multiple studies were conducted examining the effect of nozzle type, cultivation, and carrier volume on fungicidal efficacy in non-irrigated bermudagrass. Pre-application solid-tine aerification nor carrier volumes influenced SDS suppression. There was no difference among nozzle types of varying droplet size, although using nozzles that discharge coarser droplets might improve SDS suppression. The results of these studies give turfgrass managers greater insight into more effective SDS management.

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