Identifying Soybean Rust-resistant and Susceptible Populations of Kudzu to Increase Disease Monitoring Efficiency in Alabama

Soybean rust (SBR), caused by Phakopsora pachyrhizi, is considered to be one of the most damaging diseases of soybean worldwide. Monitoring for the disease in Alabama relies heavily on scouting kudzu on a biweekly basis in south and central portions of the state from late January through the end of July in areas where soybean production is minimal and is critical to help growers avoid significant yield losses from SBR. Previous studies have reported that some kudzu populations are naturally resistant or immune to infection from the pathogen which can complicate early disease detection. This study will apply that knowledge to determine locations of kudzu populations that are either resistant or susceptible to P. pachyrhizi in order to increase monitoring efficiency and reduce costs associated with the scouting program. Results show that approximately 34% of the 162 kudzu sites tested in Alabama were resistant to P. pachyrhizi. By focusing scouting efforts on SBR-susceptible kudzu sites, we will reduce costs associated with the monitoring program by approximately 25% which is critical at a time when funding for such efforts is decreasing.