Poster Session: Ecology and Epidemiology - Pathogen Dispersal

467-P

Characterizing geographic footprint of Ophiosphaerella species causing spring dead spot of bermudagrass in Virginia.
D. MCCALL (1), E. Bush (1), J. Derr (2), A. Nichols (2)
(1) Virginia Tech, Blacksburg, VA, U.S.A.; (2) Virginia Tech, Virginia Beach, VA, U.S.A.

Spring dead spot (SDS) is the most common and destructive disease of bermudagrass turf throughout the Mid-Atlantic. In addition to being unsightly, the depressed voids left behind can potentially be an injury hazard on athletic playing surfaces. Cultural management strategies of SDS are dependent on speciation of the causal agent. Two species of Ophiosphaerella are known to incite disease in the transition zone region of the United States. O. korrae is considered the dominant species in the lower transition zone (upper Southeastern states), while O. herpotrica is more prevalent in more northern regions of the zone (Maryland, Kentucky, and throughout portions of the Midwest). Localized sampling in Virginia has indicated that both species are present, but that one species tends to dominate a site-specific population. We hypothesize that while both species are present in Virginia, geography-based control recommendations can be made to minimize the severity of SDS. Symptomatic plant tissue was collected from locations in Virginia and surrounding states. Presence or absence of each species was determined using published primer sets specific to internal transcribed spacer regions of each species using real-time polymerase chain reaction (qPCR). Geo-referenced qPCR speciation results were used to provide geographical delineations of the causal agents, resulting in more accurate SDS suppression recommendations.