Fajardo, Maria Alejandra creator León, Juan Diego creator Correa, Guillermo Antonio creator Morales, Juan Gonzalo creator text periodical abstract or summary bl. continuing eng ABSTRACT Damping-off is considered one of the most serious risks for production of Pinus seedlings due to the significant losses it can cause in forest nurseries. In Colombia there is little information about the etiology of this limiting disease. Different species of the genus Fusarium have been reported as causal agents, which makes the study of the pathogenicity of this genus relevant. In this study, strain 001F of Fusarium oxysporum was obtained from the diseased tissues of P. patula seedlings. The identity of the species was determined by sequencing the internal transcribed spacer (ITS) regions. Pathogenicity tests confirmed the ability of strain 001F to cause damping-off symptoms in P. patula and P. tecunumanii. Thus, F. oxysporum strain 001F represents a significant risk to produce tree species in Colombia and in other parts of the world. Keywords: Fusarium sp., forest nurseries, pathogenicity. Publicação on-line; 44 ref.; 6 illus.; Summary (En) FUSARIUM PATOGENICIDADE VIVEIRO FLORESTAL Rio de Janeiro-RJ Instituto de Florestas - UFRRJ 1994 2025-0452 1415-0980 / ISSN 2179-8087 0nline BR2026001273 v. 26(4) p. 1-11; (2019) https://www.scielo.br/j/floram/a/pVJjjqn4XPVH3qnMJ4JdMLQ/?format=pdf&lang=en https://www.scielo.br/j/floram/a/pVJjjqn4XPVH3qnMJ4JdMLQ/?format=pdf&lang=en BR-BrBNA 260423 20260423151853.0 eng