Integrated foliar disease management to prevent yield lost in Argentinian wheat production

SIMÓN MR; CORDO, C; GOLIK, S; TERRILE, I; MORENO, V; PERELLO, ANALIA EDITH

AGRONOMY JOURNAL

AMER SOC AGRONOMY

Año: 2010 vol. 103 p. 1441 - 1451

0002-1962

Zero tillage often leads to wheat yield losses from diseases caused by necrotrophic foliar pathogens. The aim of this work was to evaluate the combined effect of tillage, nitrogen fertilization, fungicides, and resistant cultivars in reducing foliar disease severity to prevent significant yield losses. A two-year study including combinations of 1) conventional and zero tillage; 2) nitrogen fertilization rates 0, 80, or 160 kg ha-1 N; 3) two fungicide treatments (with and without a fungicide (1 L of metconazole, 9%) at growth stages (GS) 32 and 39; and 4) three wheat cultivars (Buck Bigua, Buck Brasil and Buck Pingo) was conducted in the Rolling Pampas region in Argentina. The most common foliar disease in the trial was tan spot. 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. Cultivars showed different levels of foliar disease resistance. Buck Bigua had significantly lower AUDPC values than Buck Pingo and Buck Brasil. 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. Application of N (80 or 160 kg. ha-1 N) in zero tillage plots reduced the AUDPC compared to conventional tillage plots without N. Application of 160 kg ha-1 N increased crop biomass by 71% at GS 23 and 57% at GS 83 averaged over both years compared to plots that received no nitrogen. Application of fungicide increased biomass 10% (GS 23) and 17% (GS 83). The greatest yield response to fungicide application was in plots with no N applied under zero tillage in 2002 (17% increase in yield) and at 80 kg ha-1 N in zero tillage plots in 2003 (27% increase). 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. Weather was drier at the beginning of the season in 2003 than in 2002. Yield and yield components, except TKW in 2003, increased more when wheat received 160 kg ha-1 N compared to 80 kg.ha-1 N. Although tan spot and other necrothopic diseases are known to increase in no-till systems under wheat monoculture, the results of this study indicate that developing no-till systems in wheat monoculture is possible without significant yield losses if effective disease management practices are applied