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Ecology and Epidemiology

Development of Common Blight and Accumulation of Fluoride in Red Kidney Bean Plants Exposed Continuously or Intermittently to Hydrogen Fluoride. K. L. Reynolds, Department of Plant Pathology, Cornell University, and Boyce Thompson Institute for Plant Research at Cornell University, Ithaca, NY 14853-1801; J. A. Laurence, Department of Plant Pathology, Cornell University, and Boyce Thompson Institute for Plant Research at Cornell University, Ithaca, NY 14853-1801. Phytopathology 80:211-216. Accepted for publication 4 September 1989. Copyright 1990 The American Phytopathological Society.. DOI: 10.1094/Phyto-80-211.

Four-week-old bean plants (cultivar California Light Red Kidney) were spray inoculated with rifampin-resistant Xanthomonas campestris pv. phaseoli to establish a leaf-surface population on one leaf and a lesion on another leaf of each plant. In one experiment, plants were exposed to 0 or 1 ?g F m^?3 (as hydrogen fluoride) continuously or 3 or 5 ?g F m^?3 intermittently for 15 days. In the other experiment, plants were exposed continuously to 0 or 1 ?g F m^?3 for 15 days or 3 ?g F m^?3 for 5 days or 5 ?g F m^?3 for 3 days after inoculation. Fluoride treatments in both experiments resulted in a total pollutant dose of 15 ?g F m^?3 days. Diameters of lesions were measured and leaves were sampled periodically to determine fluoride accumulation. Intermittent exposure treatments had no effect on final lesion growth. However, lesion size and expansion increased linearly with increasing fluoride in foliage. Intermittent fluoride exposure had no effect on growth of epiphytic populations of the bacterium. The development of lesions and leaf-surface populations of the pathogen exposed continuously were not affected by the exposure regime or the concentration of fluoride in air or foliage.