First report and morpho-molecular identification of Fusarium inflexum causing wilt disease in watermelon in Northeast Brazil

Watermelon ( Citrullus lanatus ) is a cucurbit of high socioeconomic importance in Brazil, especially in the Northeast region. However, its production has decreased over the years due to attacks by phytopathogenic fungi. Wilt caused by Fusarium sp. has emerged as a serious problem in watermelon production. This study aimed to characterize morphologically and molecularly the pathogen causing wilt in watermelon in Northeast Brazil. Fungal isolate was obtained from symptomatic plant, cultivated in culture medium (PDA/SNA), and analyzed for macro- and micromorphological characteristics. Molecular identification was performed through sequencing of gene regions, such as TEF1-α and RPB2, followed by phylogenetic analysis. The studies were confirmed by pathogenicity testing. Phylogenetic analysis identified Fusarium inflexum . Pathogenicity tests demonstrated that the isolate could induce disease in watermelon. This study expanded the knowledge about the diversity of Fusarium in cucurbits in Brazil. This is the first record of this species in watermelon in the region, highlighting the need for phytosanitary monitoring and integrated management strategies.