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Disease Note. Outbreak of Leaf Scald of Sugarcane, Caused by Xanthomonas albilineans, in Florida. J. C. Comstock, USDA-ARS, Sugarcane Field Station, Canal Point, FL 33438. J. M. Shine, Jr., Florida Sugar Cane League, Canal Point, FL 33438. Plant Dis. 76:426. Accepted for publication 14 October 1991. Copyright 1992 The American Phytopathological Society. DOI: 10.1094/PD-76-0426B. Leaf scald of sugarcane (Saccharum officinarum L.), although documented
in Florida since 1967 (I), has rarely been observed in commercial
plantings. The disease was found most years in breeding plots
at the Sugarcane Field Station in Canal Point, Florida, but at a less
than 1% incidence. In October 1989, however, an incidence of 9%
was observed in 1,054 stage II clonal plots (88-Series); in 1990, 17%
of 1,208 clones (89-Series) showed symptoms. No significant incidence
of leaf scald was found in commercial plantings in 1990, but in 1991
a locus of infection was found near Pahokee, Florida. There, 14%
of the stools were infected with Xanthomonas albilineans (Ashby)
Dowson in commercial plantings of two minor cultivars, CP 77-1776
and CP 78-1247. The incidence in the major cultivar CP 72-1210 (32%
of the 1990 crop) ranged from 260 to 1,335 stools per hectare. In
the cultivar CP 70-1133 (14% of the 1990 crop), the incidence ranged
from 0 to 111 stools per hectare. Koch's postulates were completed,
and the pathogen was verified against X. albilineans antiserum (serovar
1) with enzyme-linked immunosorbent assay. |