Recent advances on integrated foliar disease management in wheat in Argentina

SIMÓN, M.R.; FLEITAS, A.C. ; SCHALAMUK, S.

Fungicides - Showcases of Integrated Plant Disease Management from around the world

INTECH OPEN SCIENCES

Año: 2013; p. 3 - 34

The importance of the fungicides in the context of the integrated management of foliar diseases with special emphasis on the characteristics of the Argentinean wheat growing area is described. The chapter addresses the effect of fungicides on yield and quality when the crop is affected by the main foliar diseases. Experiments carried out in Argentina showed that fungicide and nitrogen (N) application reduced disease severity at tillering by 35 and 34% respectively, on average over two seasons. Disease was less severe in no 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 no tillage plots reduced the area under disease progress curve compared to conventional tillage plots without N. Application of 160 kg ha-1 N increased crop biomass by 71% at tillering and 57% at dough stage averaged over two seasons compared to plots that received no nitrogen. Application of fungicide increased biomass 10% at tillering and 17% at dough stage. Fungicides increased yield by 9% on average of both years. The increased yield resulted from increases in spikes.m-2 and thousand grain weight in two seasons, and also from grains.spike-1 in one season. Other experiments were also carried out in Argentina comparing the effect of N fertilization and fungicides on the severity caused by tan spot, Septoria leaf blotch and leaf rust and on the yield of wheat in the same environment. This interaction was caused by the fact that tan spot severity decreases with N fertilization, but increases for Septoria leaf blotch and leaf rust. Fungicides (combination of triazoles and strobirulins) were effective in controlling the three foliar diseases, but mainly leaf rust. The control produced by the fungicide was higher when the severity increases. Furthermore the effect of fungicides on arbuscular mycorrhizal fungi is discussed.