03176naa a2200229 a 450000100080000000500110000800800410001902200470006002400360010710000180014324501450016126000090030650003440031552020430065965300200270265300310272265300140275365300220276765300320278965300180282177301070283910641842023-06-08       2023    bl uuuu     u00u1 u    #d  a0191-2917 (print); 1943-7692 (electronic).7 a10.1094/PDIS-09-22-2123-RE2DOI1 aMARTÍNEZ, S.  aStem and sheath diseases and yield response of irrigated rice rotation systems with different intensification levels.h[electronic resource]  c2023  aArticle history: Accepted for publication 13 November 2022; Published Online 19 May 2023. -- Corresponding author: S. Martínez; smartinez@inia.org.uy -- Funding: Instituto Nacional de Investigación Agropecuaria - Uruguay, Proyecto AZ_33 "Manejo integrado de arroz para alta productividad". --  Supplementary material is available online.  aRice cultivation in South America is undergoing several intensification processes for economic reasons that cause more rice to be planted continuously on the same soils. This intensification makes the long-term biological and economic sustainability of systems questionable. Among the most common problems that threaten sustainability in intensified systems is pest and disease pressure. In this context, the primary rice diseases were studied during a 6-year period in a long-term experiment of rice rotations established in 2012 in Uruguay. The experiment consisted of six rice rotations with other crops with different duration and intensification levels. The main disease found was stem rot and, to a lesser extent, aggregate sheath spot and sheath spot of rice. These diseases are of importance in intensified rice systems because they produce sclerotia that accumulate in soils. Disease occurrence was variable among years and rotations. Stem rot incidence increased rapidly in the experiment, reaching values close to 85% in the third year, while the severity varied each year. Sheath spot incidence and severity were low and varied with the year. Continuous rice (CR) reached the highest occurrence values for stem rot, but other systems with short pastures in rotation did not differ. Aggregate sheath spot and sheath spot were of importance only in CR and in some years. When levels of intensification were compared, systems with less time (25 to 60%) occupied with rice showed lower disease severity and higher yields. Comparing CR with rice rotation with pastures of different lengths (1 to 3 years), disease occurrence was higher in 2 of the 4 years analyzed. However, yields were consistently lower, denoting that other factors are influencing productivity. Stem and sheath diseases appear not to be a limiting factor in the medium term in intensified rice systems. Also, there are several alternatives of rice intensification incorporating crops and pastures in the rotation. © 2023 The American Phytopathological Society.  aNakataea oryzae  aRhizoctonia oryzae-sativae  aSclerotia  aSoil-bome disease  aSustainable intensification  aWaitea oryzae  tPlant Disease. 2023, Volume 107, Issue 5, pages. 1593-1601. https://doi.org/10.1094/PDIS-09-22-2123-RE