Cirsium arvense – as a natural reservoir of phytopathogenic fungi.

Cirsium arvense is among the most pervasive and resilient weed species, playing a critical role in the epidemiology of phytopathogenic fungi within agroecosystems. The present study aimed to characterize fungal pathogens associated with C. arvense populations growing adjacent to cereal and legume crop fields in the North Kazakhstan region. Fungal isolates were obtained from symptomatic plant tissues, including leaves, stems, and inflorescences. Pure cultures were established through cultivation on nutrient media under controlled conditions. Molecular identification was conducted using ribosomal DNA internal transcribed spacer (ITS) region sequencing, and species-level classification was achieved by comparison with GenBank entries via BLAST analysis. The dominant fungal taxa identified were Alternaria alternata and Fusarium tricinctum. To elucidate the evolutionary placement of the isolates, a phylogenetic tree was constructed using the Neighbor-Joining method implemented in MEGA 11 software. The findings indicate that C. arvense functions as a natural reservoir for economically important phytopathogenic fungi, underscoring its epidemiological relevance and the need for integrated weed and disease management strategies in agricultural systems.