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Rhizoctonia solani AG-11 causes rice seedling disease in Texas

Shankar Gaire: Texas A&M AgriLife Research

<div>Seedling diseases are important in Texas rice production and can be caused by several seed-borne and soil-borne fungi. This study was performed to identify the causal agents of rice seedling diseases in Texas. Rice seedlings showing abnormal growth were collected from Wharton County, Texas in 2017. Infected tissues were plated in water agar and <em>Rhizoctonia solani </em>isolates were isolated based on culture morphology. These isolates were further identified as <em>R. solani</em> AG-11 based on internal transcribed space (ITS) sequence. Pathogenicity assays were conducted by planting rice in potting mix inoculated with the <em>R. solani</em> isolates and incubating them at 25<sup>0</sup>C for 15 days in a growth chamber. The <em>R. solani</em> isolates reduced seedling emergence by 96%, root growth by 55%, and shoot growth by 76% compared to non-inoculated rice seedlings.These isolates also caused necrotic lesions on mesocotyls and coleoptiles resulting root and shoot rot. <em>R. solani</em> AG-11 was determined to be a causal agent of rice seedling disease.</div>