Geographic Distribution of Ophiosphaerella Species in the Mid-Atlantic United States

Abstract

Spring dead spot (SDS) of bermudagrass (Cynodon dactylon) is primarily caused by Ophiosphaerella herpotricha and Ophiosphaerella korrae in North America. These two species respond differently to numerous management practices, grow optimally at different soil pH ranges, and differ in aggressiveness. Understanding the Ophiosphaerella species distribution in regions where SDS occurs will allow turfgrass managers to tailor their management practices toward the predominant species present. A survey was conducted in the Mid-Atlantic United States in which 1 to 14 samples of bermudagrass expressing SDS symptoms were taken from 51 athletic fields, golf courses, or sod farms across Delaware, Maryland, North Carolina, and Virginia. DNA was isolated from necrotic root and stolon tissue, amplified using species-specific primers, and detected in a real-time PCR assay. At least one isolate of O. herpotricha was recovered from 76% of the locations, and O. korrae was recovered from 73% of the locations. O. herpotricha was amplified from 55% of the samples, whereas O. korrae was amplified from 37% of the samples. There were distinct regions in the Mid-Atlantic in which either O. herpotricha or O. korrae was predominant. O. herpotricha was predominant in western Virginia, central North Carolina, Delaware, and eastern Maryland. However, O. korrae was predominant in central Maryland and Virginia as well as eastern Virginia and North Carolina. O. herpotricha was isolated from certain cultivars more frequently than O. korrae and vice versa. These survey results elucidate the geographic distribution of O. herpotricha and O. korrae throughout the Mid-Atlantic United States.