Análisis comparativo de la severidad de roya marrón de la caña de azúcar estimada durante las campañas 2009 y 2010 en Tucumán

FUNES, C.; KAIRUZ, C.R.; BERTANI, R.P.; GONZALEZ, V.; PLOPER, L.D.

Orán, Salta

Congreso; XVII Reunión Técnica Nacional de la Caña de Azúcar; 2011

Sociedad Argentina de Técnicos de la Caña de Azúcar

Sugarcane represents the main agro-industrial activity of the province of Tucuman. Sugarcane crops are affected by a number of diseases, including brown rust (Puccinia melanocephala H. & P. Sydow), which can decrease production yields. This pathology has been present in Tucuman since 1988 and was observed during the last few years with high levels of severity in varieties previously characterized as resistant. Since genetic resistance is the main management strategy for brown rust, it is important to know its prevalence in the province to anticipate and use other effective control practices. To understand the distribution of this particular disease, surveys were conducted between February and April of 2009 and 2010 in 27 locations within the province, divided into three zones: north, center and south. The disease severity was estimated with a diagrammatic scale which considers average values of percentage of affected leaf area (AFA). In 2009 there were higher levels of disease compared with 2010 and the highest values were recorded in the foothills and in the northeast of Tucuman. There were 11 frost days during the winter of 2009 compared with 1 day in 2008. The estimated average values of AFA for 2009 were 13.4% in the north, 11.6% in the center, and 18.5% in the south. In 2010, average values of AFA were all below 1% (0.6%, 0.8%, and 0.5% for northern, central, and southern areas, respectively). The brown rust severity in Tucuman was related to environmental conditions that in 2009 were more appropriate for the manifestation of the disease. The winter temperatures of 2009 may have played a key role in the low levels of disease in 2010. The Tucuman rainforest area and some northeastern areas in the province seem to have better conditions for brown rust development.