Zero tillage often leads to wheat ( Triticum aestivum L.) yield losses from diseases caused by necrotrophic foliar pathogens. The aim of this work was to evaluate the combined effect of tillage, N fertilization, fungicides, and resistant cultivars in reducing foliar disease severity to prevent significant yield losses. A 2-yr study including combinations of (i) conventional and zero tillage; (ii) N fertilization rates 0, 80, or 160 kg ha -1 N; (iii) two fungicide treatments (with and without a fungicide (1 L of metconazole, 9%)) at growth stages (GS) 32 and 39; and (iv) three wheat cultivars was conducted in the Rolling Pampas region in Argentina. The most common foliar disease in the trial was tan spot [ Pyrenophora tritici-repentis (Died.) Drechs.]. Conventional tillage reduced foliar disease severity at GS 23 by 46 and 56% and the area under disease progress curve (AUDPC) by 20 and 14% for each season, respectively compared with zero tillage. The cultivar Buck Bigua had significantly lower AUDPC values than the others. Fungicide and N application reduced disease severity at GS 23 by 35 and 34% respectively, on average over both years. Disease was less severe in zero tillage plots which received a fungicide compared to conventional tillage plots that were not treated with fungicide. In 2002 yields were greater in conventional tillage plots with 160 kg ha -1 N and fungicide application than in all other treatments. In 2003 yields were greatest in zero tillage plots with 160 kg ha -1 N and fungicide. The results of this study indicate that in spite of the increase of necrotrophic diseases, developing no-till systems in wheat monoculture is possible without significant yield losses if effective disease management practices are applied.
