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Disease Note Vein Spot Disease Caused by Gnomonia nerviseda on Pecan in Illinois. R. S. Sanderlin, Pecan Research-Extension Station, Louisiana Agricultural Experiment Station, Louisiana State University Agricultural Center, P.O. Box 5519, Shreveport 71135-5519. L. J. Grauke, Pecan Research-Extension Station, Louisiana Agricultural Experiment Station, Louisiana State University Agricultural Center, P.O. Box 5519, Shreveport 71135-5519. Plant Dis. 71:1146. Accepted for publication 11 August 1987. Copyright 1987 The American Phytopathological Society. DOI: 10.1094/PD-71-1146B. Leaves collected from a native pecan (Carya illinoensis K. Koch) in
Mercer County, Illinois, had lesions identical to those of vein spot
disease observed in Louisiana. Cultures of the fungus isolated from
diseased leaves in Illinois were morphologically similar to the vein spot
pathogen (Gnomonia nerviseda Cole) found in Louisiana. No in vitro
sporulation ofthe pathogen has been observed. Greenhouse inoculation
tests using mycelium as inoculum confirmed the pathogenicity of the
Illinois isolates, and typical symptoms of vein spot disease developed
within 30 days. Lesions on the infected foliage collected from Illinois
and on pecan seedlings inoculated with isolates from the Illinois tissue
occurred only on leaf veins, midribs, petiolules, and rachises, as is
characteristic of vein spot disease. Visual inspection of native pecans in
Mercer County suggests that vein spot is prevalent in that area. This is
the first confirmed identification of pecan vein spot disease outside the
southern United States and indicates that the disease exists near both
the southern and the northern extremes of the native pecan range (1). |