Submitted to: Plant Disease
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/26/2008
Publication Date: 4/29/2009
Citation: Chavarria, E., Subiros, F., Vega, J., Ralda, G., Glynn, N.C., Comstock, J.C., Castlebury, L.A. 2009. First report of Orange Rust of Sugarcane Caused by Puccinia kuehnii in Costa Rica and Nicaragua. Plant Dis. 93:425. Interpretive Summary: This report of orange rust in Costa Rica and Nicaragua documents the third and forth occurrence in the Western Hemisphere.previously, it was reported in Florida and Guatemala. It has intermediate symptoms on the major cultivar, CP 72-2086 in both countries. Orange rust is also found on other cultivars and the impact of the disease on commercial production in Guatemala will have to be evaluated.
Technical Abstract: Symptoms of orange rust of sugarcane were observed in Costa Rica at Coopeagri Sugar Mill located in Pérez Zeledón, San José, during July 2007 on (a complex hybrid of Saccharum L. species) cultivar, SP 71-5574, and at Providencia Sugar Mill near Muelle and at Cutris Sugar Mill near Los Chiles, in August 2007 on multiple cultivars (Pindar, Q 132, Q 138, SP 71-5574 and SP 79-2233). The same symptoms were observed during September 2007 in Nicaragua at Ingenio San Antonio, located near Chinandega, and at Ingenio Monte Rosa near El Viejo, Nicaragua on cultivar, CP 72-2086. The disease symptoms and uredinia appeared different from brown rust caused by P. melanocephala. Brown rust usually does not occur on these cultivars. Both uredinia and urediniospores were similar to those described for orange rust (1, 2). SP 71-5574 and SP 79-2233 are susceptible and CP 72-2086 is moderately susceptible to brown rust in Costa Rica and ISACP 00-1075, ISA 00-1000 and CP 72-2086 are moderately susceptible in Nicaragua. Samples from both locations (Costa Rica BPI #, Nicaragua BPI#) examined at the USDA-ARS Mycology and Microbiology Laboratory in Beltsville, Maryland showed morphological characteristics consistent with those of P. kuehnii. Analysis of the ITS1, 5.8S and ITS2 rDNA regions of the rust infecting cultivar CP 72-2086 (GenBank XXX) from Costa Rica and ISA 00-1000 from Nicaragua (GenBank XXX) confirmed their identity as P. kuehnii, the causal agent of sugarcane orange rust. Beside the cultivars already mentioned orange rust also was also confirmed on CP 72-2086, RB 73-9735, and CPCL 02-2130 in Costa Rica. These are the first reports of orange rust of sugarcane in Costa Rica and Nicaragua and the 3rd and 4th confirmations of the disease in the Western Hemisphere and Caribbean basin. 1. Comstock, J. C., et. al.. 2008. First report of Puccinia kuehnii, causal agent of orange rust of sugarcane, in the United States and in the Western Hemisphere. Plant Dis. 92:175. Ovalle, W., et. al. 2008. First report of Puccinia kuehnii, causal agent of orange rust of sugarcane, in Guatemala. Plant Dis. 92:973.