AN ITALIAN POPULATION OF ZYMOSEPTORIA TRITICI: PATHOGENICITY AND STROBILURINS SENSITIVITY

Mycosphaerella graminicola (anamorph: Zymoseptoria tritici) is the causal agent of leaf blotch, the most important foliar disease of wheat in northern and Central Europe. In Italy only during the last few years, the incidence of the disease has been increased. During 2015 a Z. tritici population was collected by different cultivar of bread and durum wheat cultivated in experimental plots and commercial fields of Emilia-Romagna region (North Italy). The aim of the study was to test the pathogenicity of each Z. tritici strains on both (bread and durum) wheat species in greenhouse. In fact, some researchers observed that the majority of strains isolated from durum wheat are lowly virulent on bread wheat cultivars, whereas the majority of strains isolated from bread wheat are lowly virulent on durum wheat (Gohari et al., 2015 Mol. Plant Pathol.,16: 931–945). Another aim was to test the sensitivity of Z. tritici population to fungicides as strobilurins by in vitro assays. The preliminary data about pathogenicity confirm the cultivar specificity in the infection process. Further data are required in order to confirm the hypothesis in an Italian Z. tritici population too. The results about sensitivity test showed an EC50 value of the wild types ranged from 0.1 to 2.88 mg/l of azoxystrobin, while the isolates collected from experimental plots and commercial fields showed EC50 value ranged from 0.01 to 5.1 mg/l. These first results show a slight decrease of sensitivity of Z. tritici isolates collected from Emilia- Romagna region (according to Gisi et al., 2005 Modern Fungicides and Antifungal Compounds IV, pp 89-101).