The first report of the teleomorph stage of the septoria nodorum blotch, Leptosphaeria nodorum, in Serbia

Abstract

Parastagonospora nodorum (teleomorph Leptosphaeria nodorum) is the causal agent of septoria nodorum blotch (SNB). It was first discovered on wheat in 1845. and is common in regions with relatively high or periodically high rainfall. P. nodorum causes symptoms on all above-ground parts of the plant, including leaves, stems, glumes, and awns. The pathogen overwinters on wheat crop residues in the form of pseudothecia and pycnidia. Ascospores released from pseudothecia typically serve as the primary source of inoculum, but conidia released from pycnidia on crop residues can also infect seedlings. Additionally, the fungus is known to survive on seeds in the form of dormant mycelium, making infected seeds a potential source of primary infection. During the 2022/2023 growing season, precipitation totals in April (63.9 mm) and May (124.8 mm) exceeded seventeen-year averages, creating conditions conducive to occurence of SNB. Microscopic examination of lesions on leaves of wheat variety revealed the presence of the sexual stage (L. nodorum) for the first time in Serbia. The asexual stage (P. nodorum) was observed on infected ears of different varieties. This study highlights the need for more attention in monitoring conditions that could lead to outbreak SNB in wheat production areas in Serbia.