The Fungus HL-29: A Promising Weed Pathogen with Bioherbicidal Potential and Crop Safety

The herbicidal efficacy and crop safety of Fusarium acuminatum strain HL-29, an endophytic fungus isolated from infected Amaranthus retroflexus in Qinghai Province, were evaluated. In vitro leaf assays demonstrated its pathogenicity against four broadleaf weeds, with efficacy ranked as follows: <i>Elsholtzia densa</i> = <i>Senecio vulgaris</i> = <i>Chenopodium album</i> > <i>Malva verticillata</i>. Pot trials further confirmed that the HL-29 fermentate caused 100% disease incidence in <i>S. vulgaris</i>, <i>C. album</i>, and <i>E. densa</i>. Notably, the strain showed no pathogenicity toward seven major local crops, indicating excellent selectivity. Scanning electron microscopy (SEM) revealed key morphological changes during the infection process on <i>C. album</i> leaves. These results establish F. acuminatum HL-29 as a promising biocontrol candidate against broadleaf weeds in the Qinghai-Tibet Plateau, providing a theoretical foundation for developing alpine-adapted mycoherbicides.