Fusarium wilt caused by Fusarium oxysporum f. sp. lycopersici (FOL) is one of the main diseases affecting tomato plants. Three races (races 1, 2 and 3) of the pathogen have been described around the world, including in Brazil. Nova Friburgo, Rio de Janeiro State, is one of the leading tomato producing regions. During summer, farmers have reported severe losses caused by wilt disease. The present work aimed to identify and characterize the disease and predominant FOL races found in this region. The study was conducted in 41 family farms on 246 harvested tomato plants. Fusarium wilt was identified based on visual diagnosis, isolation and microscopy tests. Race identification was performed using: (a) differential cultivars; (b) conventional PCR and (c) gene sequencing. From all the isolates obtained, 38 were characterized as Fusarium spp. and 24 (63.2%) were identified as race 3 of FOL by differential cultivars. From the 24 FOL isolates, eighteen were randomly selected for race identification by gene sequencing. SIX primers (SIX3, SIX4 and SIX-G12A-F2) were not efficient to characterize races 1, 2 and 3 of FOL. Primers uni, sp12, sp. 23, sprl, as well as, primer SIX3 only allowed to identify race 3. The SCAR OP-Z4 marker was not able to identify race 2. Our study shows the predominance of FOL race 3 in the Nova Friburgo region. Moreover, primers developed to identify FOL races in other parts of the world are not well adapted to differentiate Brazilian FOL isolates.

由尖孢镰刀菌f.引起的镰刀菌枯萎病。sp. lycopersici (FOL) 是影响番茄植株的主要病害之一。该病原体的三个种族（种​​族 1、2 和 3）已在世界各地被描述，包括在巴西。里约热内卢州的 Nova Friburgo 是主要的番茄产区之一。在夏季，农民报告了枯萎病造成的严重损失。目前的工作旨在识别和表征该地区发现的疾病和主要的 FOL 种族。该研究是在 41 个家庭农场对 246 株收获的番茄植物进行的。镰刀菌枯萎病是根据视觉诊断、隔离和显微镜检查确定的。使用以下方法进行种族鉴定： (a) 差异栽培品种；(b) 常规 PCR 和 (c) 基因测序。从获得的所有分离株中，38 个被鉴定为镰刀菌属 和 24 (63.2%) 种被差异栽培品种鉴定为 FOL 的小种 3。从 24 个 FOL 分离株中，随机选择了 18 个通过基因测序进行种族鉴定。六个引物（SIX3、SIX4 和 SIX-G12A-F2）不能有效地表征 FOL 的种族 1、2 和 3。引物 uni、sp12、sp。23、sprl 以及引物 SIX3 仅允许识别种族 3。SCAR OP-Z4 标记无法识别种族 2。我们的研究表明 FOL 种族 3 在 Nova Friburgo 地区占优势。此外，为识别世界其他地区的 FOL 种族而开发的引物并不适合区分巴西 FOL 分离株。