Sugarcane brown rust control and its effect on yields of LCP 85-384 during four growing seasons in Tucumán, Argentina

FUNES, C.; HENRIQUEZ, D.D.; BERTANI, R.P.; JOYA, C.M.; GONZALEZ, V.; ROMERO, E.; PLOPER, L.D.

Guayaquil

Workshop; ISSCT XI Pathology and IX Entomology Workshops; 2015

International Society of Sugar Cane Technologists (ISSCT)

Sugarcane represents the main agro-industrial activity in Tucumán province, 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 high severity levels of the disease have been observed in varieties previously characterized as resistant. The use of fungicides to manage brown rust and the effect of the disease on LCP85-384 yield was evaluated in a field experiment conducted during four growing seasons (2009, 2010, 2011 and 2013). During 2009, 2011 and 2013, chemical treatments including a fungicide (pyraclostrobin and epoxiconazole), applied at 15-day intervals at 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 rust severity values observed under chemical treatments were 4.4%, 8% and 12% in 2009, 2011 and 2013, respectively. In 2010 no reduction was recorded, since environmental conditions did not favor the development of the disease altogether. 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 surmounted by new variants of the pathogen.