Previous Article | Next Article ![]()
Appl. Environ. Microbiol., Jul 1996, 2560-2566, Vol 62, No. 7
SS Hirano, LS Baker and CD Upper
Observational and microclimate modification experiments were conducted
under field conditions to determine the role of the physical environment in
effecting large increases in phyllosphere population sizes of Pseudomonas
syringae pv. syringae, the causal agent of bacterial brown spot disease of
snap bean (Phaseolus vulgaris L.). Comparisons of daily changes in
population sizes of P. syringae on three plantings of snap bean cultivar
Cascade and one of cultivar Eagle with weather conditions indicated a
strong association of rainfalls with periods of 1 to 3 days in duration
during which increases in bacterial population sizes were greater than
10-fold and up to 1,000-fold. The effects of rain on populations of P.
syringae were explored further by modifying the microclimate of bean plants
in the field with polyethylene shelters to shield plants from rain and
fine-mesh inert screens to modify the momentum of raindrops. After each of
three separate intense rains, the greater-than-10-fold increases in
population sizes of P. syringae observed on plants exposed to the rains did
not occur on plants in the shelters or under the screens. The screens
decreased the velocity and, thus, the momentum of raindrops but not the
volume or quality of rainwater that fell on plants under the screens. Thus,
the absence of increases in population sizes of P. syringae on plants under
the screens suggests that raindrop momentum plays a role in the
growth-triggering effect of intense rains on populations of P. syringae on
bean plants under field conditions.
Copyright © 1996, American Society for Microbiology
Raindrop Momentum Triggers Growth of Leaf-Associated Populations of Pseudomonas syringae on Field-Grown Snap Bean Plants
Department of Plant Pathology and Plant Disease Resistance Research Unit, USDA Agricultural Research Service, University of Wisconsin, Madison, Wisconsin 53706
This article has been cited by other articles:
Copyright © 2009 by the American Society for Microbiology. For an alternate route to Journals.ASM.org, visit: http://intl-journals.asm.org | More Info»