Jonathan Patrick Amie
LSU
Baton Rouge, Louisiana, United States
David Moseley
Assistant Professor/Soybean Specialist
Dean Lee Research & Extension Center, Louisiana State University
Alexandria, Louisiana, United States
Terry Spurlock
Associate Prof-Plant Pathologist
Department of Entomology & Plant Pathology, University of Arkansas System Division of Agriculture
Little Rock, Arkansas, United States
Tom W. Allen
Extension/Research Professor
Delta Research & Extension Center, Mississippi State University
Stoneville, Mississippi, United States
Vinson P. Doyle
Associate Professor
Department of Plant Pathology & Crop Physiology, Louisiana State University, Baton Rouge, LA 70803
Baton Rouge, Louisiana, United States
Trey Price, n/a
Associate Professor
Macon Ridge Research Station, Louisiana State University, Winnsboro, LA 71295
Winnsboro, Louisiana, United States
Boyd Padgett
Professor
Dean Lee Research & Extension Center, Louisiana State University
Alexandria, Louisiana, United States
Joseph H. LaForest
Co-Director, Southern IPM Center
University of Georgia
Tifton, Georgia, United States
Abdulkadir I. Dalha (he/him/his)
Post Doctoral Researcher
Department of Plant Pathology & Crop Physiology, Louisiana State University
Baton Rouge, Louisiana, United States
Stephanie Ramos
Department of Plant Pathology & Crop Physiology, Louisiana State University
Baton Rouge, Louisiana, United States
Beatriz M. Carvalho
Postdoctoral Researcher
Department of Plant Pathology & Crop Physiology, Louisiana State University
Baton Rouge, LA, USA
Sara Thomas-Sharma
Assistant Professor
Department of Plant Pathology & Crop Physiology, Louisiana State University
Baton Rouge, Louisiana, United States
Cercospora leaf blight (CLB) is a major foliar disease of soybean in the Mid-southern United States and is caused by Cercospora cf. flagellaris, Cercospora cf. sigesbeckiae and less commonly Cercospora kikuchii. The contribution of these species to CLB incidence can differ by geography and may impact management strategies. From 2022 to 2024, 382 isolates (82 from MS, 60 from AR, and 240 from LA) were collected from commercial soybean fields across 13 counties. Using C. flagellaris-specific conventional PCR assays, 59% of the isolates were identified as C. flagellaris (with 42%, 65%, and 51% from AR, LA, and MS respectively). The proportion of isolates belonging to C. sigesbeckiae and C. kikuchii will be determined using species-specific quantitative PCR assays. CLB management relies heavily on foliar fungicides. Increasing levels of resistance to common fungicide chemistries such as quinone outside inhibitors (QoIs) have been documented in the CLB pathogen population since 2011. A loop mediated isothermal amplification (LAMP) assay that detects the G143A mutation associated with QoI resistance showed that 48% of the sampled isolates were resistant (with 37% in AR, 53% in LA, and 40% in MS), though resistance frequency differed between counties. Ongoing research aims to determine QoI resistance by species and to develop rapid protocols to detect resistance to additional chemical classes that are commonly used, such as demethylation inhibitors. EDDMaps, a web-based mapping system for documenting invasive species will be used to make our results accessible to stakeholders.