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Report of Sugarcane yellow leaf virus in Ecuador, Guatemala, and Nicaragua

In 1998, sugarcane plants with symptoms similar to yellow leaf syndrome were observed in Ecuador, Guatemala, and Nicaragua. These plants showed yellowing of the central portion of the third to sixth leaves on the abaxial surface from the youngest expanding spindle leaf. Intense yellowing and necrosis of the leaf tip and the central portion of the leaf blade near the midrib occurred in severe cases. A tissue blot immunoassay was used to detect Sugarcane yellow leaf virus (SCYLV) in the midrib of the top visible dewlap leaf (2) using an antiserum specific to a Florida isolate of SCYLV (1). Since the virus can be detected in asymptomatic plants, leaf samples were collected from both symptomatic and asymptomatic plants. Symptom expression was most intense in plants at maturity that were under stress. Cut ends of leaf samples were imprinted on nitrocellulose membranes in the country of origin, and control samples of healthy and SCYLV-infected leaves were imprinted in Florida on each membrane prior to serological processing. The results from the following locations and cultivars, and the ratio of SCYLV-positive samples over the total samples is indicated: Milagro, Ecuador, PR 70-2085 (11/24) and PR 76-3385 (48/63) in 1999; Escuintla, Guatemala, CP 57-603 (1/10), CP 73-1547 (0/10), CP 72-2086 (120/308), PR 75-2002 (8/11), PR 78-294 (10/10), and PR 87-2080 (13/13) in both 2000 and 2001; Tipitapa, Nicaragua, L 68-40 (21/70) in 1998; and Chinandega, Nicaragua, CP 72-2086 (30/30) and CP 74-2005 (13/45) in 2000. CP 72-2086 is a major commercial cultivar in Central American countries and was infected in both Guatemala and Nicaragua. SCYLV was detected in 9 of 10 cultivars sampled. An exception was noticed in CP 73-1547 in Guatemala where none of the 10 plants tested were infected; however this cultivar has a high incidence of SCYLV in Florida. Only 1 of 10 samples of CP 57-603 was SCYLV positive in Guatemala; however, this cultivar has a low incidence of infection in Florida and is considered more resistant than the other CP cultivars sampled. To our knowledge, this is the first report SCYLV in Ecuador, Guatemala, and Nicaragua.

References: (1) S. M. Scagliusi and B. E. L. Lockhart. Phytopathology 90:120, 2000. (2) S. Schenck et al. Sugar Cane 4:5, 1997.