Can fungi associated with seeds be an important source for the biological control of invasive plants? Urochloa (=Brachiaria) as a case study

The introduction and naturalization of exotic species in Brazil, favored by their high adaptability and the absence of natural enemies, are among the main drivers of biodiversity loss. A notable example is the genus Urochloa , originally introduced for pasture formation but now recognized as one of the major groups of invasive plants capable of suppressing native species regeneration and altering ecological dynamics. In view of the need for sustainable alternatives to manage these species, this study investigated fungi associated with U. decumbens seeds to select isolates with potential for biological control. Seeds collected from three distinct areas were subjected to the Blotter test, resulting in the isolation and identification of 199 fungi, with Bipolaris being the most frequent genus. Three strains of B. gossypina (F11, F13, and F15) were evaluated for pathogenicity on seeds and seedlings of U. decumbens , U. brizantha , and U. ruziziensis , as well as on five native Cerrado species ( Cecropia pachystachya , Luehea divaricata , Eugenia dysenterica , Handroanthus ochraceus , and Guazuma ulmifolia ). The isolates significantly reduced germination and caused necrosis and death in the invasive grasses, without affecting the native species tested. These findings indicate that fungi associated with the seeds of invasive plants may represent a promising and ecologically safe alternative for the management of Urochloa spp., particularly in areas where herbicide use is restricted.