Incidence and Development of Bacterial Leaf Scorch of Elm on the National Mall    (View PDF)

J. L. Sherald, E. N. Patton, T. M. Stidham, and C. L, Favre

Abstract: Approximately 600 elms on the National Mall in Washington D. C. were surveyed for 6 years for symptoms of bacterial leaf scorch caused by Xylella fastidiosa. The mean disease incidence over the course of the study was 30% and increased by approximately 10% over 6 years. Twenty-eight percent of the affected trees had symptoms in more than 25% of their crowns. Symptom severity fluctuated from year to year. Of the trees first detected with symptoms in 1986 only 18% had a higher symptom rating after 6 years, while 51 % had fewer or no symptoms. Trees 20-30 cm dbh were the most affected, while those in the 1-10 cm class were the least affected. Affected trees occurred throughout the planting.

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https://doi.org/10.48044/jauf.1994.004