Submitted to: Sugar Cane Growers Cooperative Agricultural Forum
Publication Type: Abstract Only
Publication Acceptance Date: 4/25/2008
Publication Date: 4/28/2008
Citation: Comstock, J.C. 2008. Sugarcane Rusts and Cultivar Options in Florida. Sugar Cane Growers Cooperative Agricultural Forum. Interpretive Summary: The presentation to the Sugar Cane Growers Cooperative discussed the impact of orange rust on commercial sugarcane cultivars in South Florida. Recommended cultivar, CP 80-1743, that occupies approximately 20% the acreage in Florida be phased out of production because of its susceptibility.
Technical Abstract: Sugarcane Rusts and Cultivar Options in Florida In late June 2007, an outbreak of rust was observed in Florida on CP 80-1743, a variety previously resistant to brown rust caused by Puccinia melanocephala. The rust appeared only on the upper leaves and the pustules were all young actively sporulating and symptoms did not appear typical of brown rust. Closer morphological observations followed by molecular verification identified the pathogen as Puccinia kuehnii, the causal agent of orange rust a sugarcane disease found in South East Asia. Unlike brown rust the orange rust development did not diminish with warmer temperatures of summer and continued to develop on this variety throughout the remainder of the growing season. Growers reported a decrease in sucrose in CP 80-1743 resulting from defoliation and the growth of new shoots late in the season. In February 2008, CP 80-1743 plant crop fields had severe orange rust development that has not decreased since then. Consequently, this variety is no longer recommended for commercial production and should be phased out of production. Current ARS research is focusing on identifying alternative brown and orange rusts resistant varieties for commercial production using new field inoculation procedures and reactions under natural infection conditions. Due to the longer period of orange rust development it may be more damaging than brown rust.