First report of Rhizoctonia solani AG4 causing stem necrosis in sesame in Southwest Texas.
In October 2015, root rot and stalk rot symptoms were noted on sesame (Sesamum indicum) in an irrigated commercial production field in Uvalde County, Texas, USA. Stems had dark brown lesions just above the soil line and plants with advanced symptoms exhibited necrosis progressing up the stem. Stunting, late season lodging and reduced yield were associated with areas of disease in approximately 5% of the 45-ha field. The causal pathogen was isolated and identified as Thanatephorus cucumeris AG4 based on morphological, molecular and pathogenicity analyses. This is thought to be the first report of T. cucumeris AG4 infecting sesame in Texas, USA.