Sugarcane brown rust control and its effect on yields of LCP85-384 during four growing seasons in Tucumán, Argentina.

FUNES C; HENRIQUEZ D; BERTANI RP; JOYA CM; GONZÁLEZ V; ROMERO E; PLOPER LD

Guayaquil

Workshop; ISSCT XI Pathology and IX Entomology Workshops; 2015

ISSCT

Sugarcane represents the main agro-industrial activity of the province of Tucumán, Argentina. This crop is affected by a number of diseases, including brown rust (Puccinia melanocephala H. & P. Sydow), which can decrease production and yields. Brown rust has been present in Tucumán since 1988 but in recent years has been observed with high levels of severity in varieties previously characterized as resistant. The use of fungicide to manage brown rust and the effect of the disease on yield of LCP 85-384 was evaluated in a field experiment conducted during four growing seasons (2009, 2010, 2011 and 2013). During 2009, 2011 and 2013, chemical treatments, which included a fungicide (pyraclostrobin y epoxiconazole) applied at 15-day intervals during six different stages of the epidemic, reduced the area under the disease progress curve (AUDPC) by 56%, 43% and 45% , respectively, in comparison with the untreated control. The maximum values of rust severity observed in the chemical control were 4.4 %, 8 % and 12% in 2009, 2011 and 2013, respectively. In 2010 no reduction was recorded since the environmental conditions were no favorable for the disease. The disease had no effects on sugarcane yield components during 2009, 2011 and 2013. No significant differences were detected for cane yield or sugar yield, in spite of the significant differences in brown rust severity between the untreated control and the chemical treatments. Although the use of resistant cultivars is the best option for brown rust management, fungicide application may be considered in those cases where resistance is seriously overcome by new variants of the pathogen.