Resumo

GERARD, G.S; FLEITAS, M.C; SCHIERENBECK, M  e  SIMON, M.R. Eficacia de control y residualidad de curasemillas sobre enfermedades foliares de trigo. FAVE. Secc. Cienc. agrar. [online]. 2015, vol.14, n.2. ISSN 1666-7719.

Control efficacy and residual efficacy of seed treatments on foliar diseases of wheat Seed treatments are usually effective few days after sowing. However, actives recently developed can protect seedlings for longer periods. Thus, they can be an alternative to early foliar applications for disease control. Additionally, its effect can be influenced by nitrogen fertilization. The aims of this study were: i) to determine the effect and control efficacy of different seed treatments on the three main foliar diseases of wheat: Leaf Rust (LR), Tan Spot (TS) and Septoria Leaf Blotch (SLB); ii) to determine its residual efficacy throughout the crop cycle; iii) to assess the effect of different nitrogen doses on disease development; iv) to assess the effect of different nitrogen doses on disease control efficacy. The experiment was performed in pots with a completely randomized design. Three factors were included: foliar diseases (LR, TS and SLB); seed fungicide treatments [Untreated control (UT), PremisTM (Triticonazole-10%) 25 cm3.100 Kg-1 of seed (P), PremisTM + SistivaTM (Fluxapyroxad 333g.L-1) 30 cm3.100 Kg-1 of seed (P + S1), and PremisTM + SistivaTM 75 cm3.100 Kg-1 of seed (P + S2)] and nitrogen (0 KgN.ha-1, 90 KgN.ha-1, y 180 KgN.ha-1). Eight inoculations along the crop cycle were performed with every pathogen, evaluating the severity in each of them. The area under the disease progress curve, control efficacy of the seed treatment and its residual efficacy were calculated. All seed treatments had significant differences of disease control compared to the untreated. Higher levels of control were observed with P + S2 with maximum values closed to 80% in the first evaluated dates. Seed treatments containing mixtures showed significant higher values of residual efficacy compare to the Triticonazole-only. This efficacy, was significant compared to UT until 66 and 55 days since the first inoculation, respectively. No significant differences were observed in control efficacy with different nitrogen doses, however, they did affect disease development. Seed treatments had effect on disease control, varying in control efficacy and residual efficacy depending on the type of disease, active ingredient and its dose.

Palavras-chave : Seed fungicide treatments; Foliar diseases; Control efficacy; Residual efficacy; Wheat.

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