RT info:eu-repo/semantics/article
T1 Blast disease associated with grass weeds in rice production systems of Paraguay
T2 Pyriculariosis asociada a malezas en sistemas de producción de arroz en Paraguay
A1 Morinigo Giménez, Beatriz Karina Grisel
A1 Urashima, Alfredo
A1 Chávez, Alice Rocío
A1 Fernández Gamarra, Marta Alicia
A1 Talavera Stefani, Liliana Noelia
A1 Duarte, Rocío
A1 Cazal Martínez, Cinthia Carolina
A1 Quintana Viedma, Lidia Augusta
A2 Universidad Nacional de Itapúa
A2 Universidad Nacional de Asunción. Centro Multidisciplinario de Investigaciones Tecnológicas
AB Background: Several fungal species within the genus Pyricularia are associated with blast diseases affecting Poaceae crops, including wheat, rice, oat, barley, triticale, and various grass weeds. Among these, Pyricularia oryzae is recognized as a major pathogen due to its significant impact on cereal production worldwide. The fungus can survive on weed hosts, potentially serving as inoculum reservoirs. Objective: To characterize grass weed species acting as alternative hosts for Pyricularia spp. in rice agroecosystems in Paraguay. Methodology: During the 2020/2021 rice season, symptomatic weed samples exhibiting elongated or elliptical lesions with reddish-brown margins and lighter centers were collected across major rice-producing regions. Samples were processed at the Microbiology and Biotechnology laboratories of the Facultad de Ciencias y Tecnología, Universidad Nacional de Itapúa, and the Instituto Paraguayo de Tecnología Agraria (IPTA). Results: Morphological characterization of isolates cultured on oat agar revealed grayish to dark-gray colonies, with conidia hyaline, pyriform to obclavate, and containing two transverse septa. Molecular identification based on ITS region sequencing confirmed isolates from Cynodon dactylon as Pyricularia grisea (99.8% similarity) and from Echinochloa sp. as Pyricularia oryzae (100% similarity). Pathogenicity assays in rice seedlings (cv. IRGA 424) reproduced typical blast symptoms for the rice-derived isolate, whereas the Cynodon dactylon- and Echinochloa-derived isolates elicited differential reactions, including hypersensitive, incompatible, and mild blast-like symptoms. Implications: These findings underscore the epidemiological role of grass weeds as alternative hosts and potential inoculum reservoirs of Pyricularia spp., emphasizing the need to integrate weed monitoring and management into comprehensive blast disease control strategies in rice cultivation systems. Conclusion: Grass weed species present in rice agroecosystems of Paraguay were identified as reservoirs for Pyricularia spp., highlighting their potential role in pathogen survival and dissemination within rice fields.
PB Universidad Autónoma de Yucatán. Facultad de Medicina Veterinaria y Zootecnia
SN 1870-0462
YR 2025
FD 2025-12
LK http://hdl.handle.net/20.500.14066/4731
UL http://hdl.handle.net/20.500.14066/4731
LA eng
NO Corresponding author. C. Cazal-Martínez; L. Quintana; ccazal@rec.una.py; lquintana@uni.edu.py.
NO Consejo Nacional de Ciencia y Tecnología
DS MINDS@UW
RD 03-sep-2026