Causal agent of wheat blast (Magnaporthe oryzae): Occurrence and risks for wheat production in Serbia

Abstract

Magnaporthe oryzae (anamorph Pyricularia oryzae) is the causal agent of wheat blast. Apart from being a pathogen of commercially significant plant species, it also infects weeds. Within the species M. oryzae, several pathotypes exist, with the pathotype Magnaporthe oryzae Triticum (MoT) infecting wheat and several other grass species. M. oryzae was first discovered in Brazil in 1985 and has since posed a threat to wheat production in various parts of the world, including Bangladesh and European Union countries. The MoT pathogen can infect all above-ground parts of the plant, but the most common symptoms appear on the ears and closely resemble symptoms of fusarium head blight. During the 2022/2023 growing season, precipitation levels in April and May at the Rimski šančevi exceeded seventeen-year averages, while the temperature in May was within the multi-year average range. These conditions created a favorable environment for the emergence of M. oryzae. Microscopic examination of infected ears revealed the presence of conidia from the asexual generation of Pyricularia oryzae. Considering that MoT is not classified as a quarantine pathogen in many EU countries, this study highlights the risk of the presence of M. oryzae in Serbia, as well as the importance of monitoring the occurrence of M. oryzae in weeds, grasses, and cereal grains to take timely action in protecting crops from this pathogen.