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Ecology and Epidemiology

Tomato Leaf Trichomes, a Habitat for Resident Populations of Pseudomonas tomato. R. W. Schneider, Department of Plant Pathology, University of California, Davis, CA 95616, Present address of senior author: Department of Plant Pathology, University of California, Berkeley, CA 94720; R. G. Grogan, Department of Plant Pathology, University of California, Davis, CA 95616. Phytopathology 67:898-902. Accepted for publication 31 January 1977. Copyright © 1977 The American Phytopathological Society, 3340 Pilot Knob Road, St. Paul, MN 55121. All rights reserved.. DOI: 10.1094/Phyto-67-898.

A large portion of the resident populations of Pseudomonas tomato on tomato leaves was not killed by surface sterilization with sodium hypochlorite, indicating that many of the bacteria on the leaf surface were not exposed. Microscopic examination of trichomes on noninjured, inoculated leaves revealed that many of the apparently intact but nonliving trichomes were colonized by bacteria. Injury of the basal cells of trichomes, followed immediately by inoculation, resulted in more lesion production than in noninjured controls, but only when leaf surfaces were maintained dry after inoculation. However, if inoculation was delayed for 24 hr after trichomes were injured, lesion production was not enhanced. Tomato mutants, deficient in leaf hairs, supported relatively small resident populations under dry conditions, and the resident populations did not increase as much as in pubescent mutants after the leaves were exposed to free moisture.