Outbreak of Sycamore Leaf Scorch in the Carolinas. R. A. Haygood, Department of Plant Pathology and Physiology, Clemson University, Clemson, SC 29634. W. Witcher, and R. K. Jones. Department of Plant Pathology and Physiology, Clemson University, Clemson, SC 29634, and Department of Plant Pathology, North Carolina State University, Raleigh 27695. Plant Dis. 72:644. Accepted for publication 29 March 1988. Copyright 1988 The American Phytopathological Society. DOI: 10.1094/PD-72-0644C.
Fastidious, xylem-inhabiting bacteria (FXIB) were cultured from
and demonstrated to cause leaf scorch of sycamore (Platanus
occidentalis L.) in 1983 (1). Symptoms of leaf scorch were observed on
approximately 25% of the sycamores in the vicinity of Clemson, South
Carolina, and about 50% of those in the vicinity of Raleigh, North
Carolina, in the summer and fall of 1987. Positive serological reactions
were obtained using ELISA kits sensitive to FXIB in general (Agdia,
Inc., Mishawaka, IN) with extracts from petioles of 17 trees showing
scorch symptoms in September. FXIB were also detected by ELISA in infected sycamore petioles collected in October and stored for 3 mo at 4 C, in buds of infected sycamores in January 1988, and in a grapevine
inoculated with Pierce's disease FXIB. Negative serological reactions
were obtained with extracts from petioles and buds of six asymptomatic
sycamores and a healthy grapevine.