2.4. In-field Artificial Infection Trials

Field trials in the growing season 2014–2015 were performed in Montelibretti (CREA-IT) and in Rome using durum wheat variety Svevo and the same strains of P. nodorum ST15465 and Z. tritici ST18258 used for artificial inoculations (see Section 2.3). In the crop season 2014–2015, we have 12 plots in two different fields located in Rome (latitude 41.969277; longitud 12.464256; m.a.s.l. 20) and in Montelibretti (RM) (latitude 42.129287; longitude 12.63969; m.a.s.l. 25) at the CREA–Research Centre for Engineering and Agro-Food Processing, CREA-IT. The Svevo wheat variety was sown (viable seeds: 450/m²) in plots of 1.5 m × 2 m (3 m²) using a randomized block design with three replicates. Different experimental conditions were set up (Table 1).

Different experimental conditions used on durum wheat cultivars to study the effect of Tramesan on StagonosporaNodorumBlotch and SeptoriaTriticiBlotch in Montelibretti (Rome) and in Rome (Italy) field trials performed by the Council for Agricultural Research and Economics—Research Centre for Engineering and Agro-Food processing (CREA-IT) in the 2014–2015 growing season.

Each plot in the two fields contained n = 250 plants. The number of plants was fewer than the seeds, probably due to the considerable presence of birds at the time of sowing. The trials were performed in three plots per thesis (mock, T, Inf, T + Inf). Inoculation for the artificial contamination in the field plots was prepared as indicated in Section 2.1. As in Table 2, the plants were treated with Tramesan by spraying at the booting growth stage, GS 47, for SNB trials, and at stem elongation growth stage, GS 37, for STB trials. The inoculation of wheat plants with foliar pathogens was carried out by spraying conidial suspensions (P. nodorum: 10⁶ spores/mL at growth stage GS 49; Z. tritici: 10⁷ spores/mL at growth stage GS 39) containing Tween 20 surfactant (0.1% v/v) as previously described [22]. The inoculated plots were covered with transparent plastic sheets for 48 h, providing a humid, saturated atmosphere necessary for spore germination and penetration into the leaves. Over that plastic sheet, a plastic shade was used to protect the plants from direct sunlight. Infections were assessed by visual observations of symptoms, such as STB and SNB severity on the flag leaf at growth stage GS 83, according to Iori et al., 2015 [24]. In the field, diseases were assessed every 7 to 10 days until the ripening stages. All field trials were harvested at maturity.

Disease severity as measured at 7 dai at the second leaf stage according to Liu’s scale (0–5) [23] in the durum wheat varieties (Svevo and Duilio) inoculated with P. nodorum ST15465 or Z. tritici ST18258. Mock: without Tramesan, non-inoculated. T: treated with Tramesan; Tr + Inf: treated with Tramesan, inoculated with the pathogen; Inf: inoculated with the pathogen. Fisher test on n = 48 × 2 biological repetitions.

^a,b refer to Figure 1 upper and lower.