Powdery mildew is a common, economically important disease in the wheat growing area of Serbia. A large-scale virulence survey of its causal agent Blumeria graminis f. sp. tritici population was performed in the period 1995–2013. A total of 1013 isolates were recovered from the collected chasmothecial samples. Among them, 862 unique pathotypes were identified using a differential set of 20 wheat lines with known powdery mildew (Pm) resistant genes. The pathogen was highly diverse. Number of virulence genes (virulence complexity) per isolate was large, supporting a constant need to extend the differential set of wheat with newly identified Pm genes. Virulence frequencies to Pm6, Pm7, and Pm5+8 were high throughout the 19-year period, in contrast with that to Pm5+6, which was consistently at a low level. The most significant change in the population was observed for virulence to the Pm2+4b+6 gene combination, with an increasing frequency of virulence to this gene combination over the years. High virulence complexity and genetic diversity of the population are the most influential factors for the damaging epidemics that this pathogen can cause.

Monitoring changes in the prevalence of Fusarium species and toxin production is an important tool for the integrated control of Fusarium head blight (FHB). However, methods for the high-throughput screening of Fusarium populations have been developed using isolates with limited geographic origins. In this study, we used species- and trichothecene-specific primers to monitor the F. graminearum species complex (FGSC) originating from Serbia. We also tested the applicability of the primers to the surveillance of FHB. We analyzed two hundred and ten isolates collected from thirty two locations and five winter wheat varieties over a three-year period. Using multiple correspondence analysis (MCA), we investigated associations between Fusarium-damaged kernels (FDK) and location, variety, members of the FGSC, and their predisposition for mycotoxin production. The results revealed that the species-specific primers were not specific for 11% of the F. graminearum population. The primer sets were 98.5%, 95.2%, and 92.4% effective in the multilocus genotyping of Tri7, Tri3, and Tri5 genes, respectively. We found that individual wheat varieties were associated with isolates that could not be characterized using species- and trichothecene-specific primers. Alternaria spp. had a significant influence (p < 0.001) on grain infection with F. graminearum, indicating the necessity to further investigate its impact on the pathogenesis of the F. graminearum clade.

The utilization of production systems with reduced chemical input renewed the interest in Ustilago nuda and Pyrenophora graminea. The investigations of seed fungicide treatments are more related to their efficacy than to their contribution to yield gain. The data were collected from research and development trials on fungicide efficacy against U. nuda and P. graminea conducted from 2014 to 2020 in Serbia. Partial least squares, multiple stepwise regression and best subset regression were used for statistical modeling. The total number of plants infected with U. nuda and P. graminea per plot differed significantly in the seven-year period. Shifts in the predominance of one pathogen over the other were also shown. Temperature, total rainfall and relative humidity in flowering time (p < 0.001) influenced the occurrence of both pathogens. The strongest impact on yield loss was observed for temperature in the phenological phases of leaf development (p = 0.014), temperature in flowering time (p < 0.001) and total number of plants infected with U. nuda and P. graminea per plot (p < 0.001). Our results indicated that regression models consisting of both biotic and abiotic factors were more precise in estimating regression coefficients. Neither fungicidal treatment had a stable contribution to yield gain in the seven-year period.