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STUDIES ON BACTERIA ASSOCIATED WITH THE CHOCOLATE‐SPOT DISEASE OF BROAD BEANS 1
Author(s) -
RIKER A. J.,
RIKER REGINA S.
Publication year - 1932
Publication title -
annals of applied biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.677
H-Index - 80
eISSN - 1744-7348
pISSN - 0003-4746
DOI - 10.1111/j.1744-7348.1932.tb04306.x
Subject(s) - biology , inoculation , organism , isolation (microbiology) , bacteria , pathogenic bacteria , microbiology and biotechnology , botany , incubation period , horticulture , incubation , paleontology , genetics , biochemistry
SUMMARY A bacterium which resembles Ps. seminum Cayley has been isolated from broad beans showing symptoms of chocolate spot in the field. The broad‐bean organism was found to be vigorously pathogenic to broad beans and to garden peas grown in the greenhouse. Two strains have both been passed five successive times through the cycle of isolation, inoculation into broad‐bean plants, the production of disease, and re‐isolation. Further study is necessary before a causal connection between this organism and the disease can be regarded as established. Temperatures between 20 and 30 o C. and high humidity favour infection. Histological studies of stems which became diseased following puncture inoculations showed the presence of the broad‐bean organism within the vessels, in the intercellular spaces, and inside the cells of the invaded tissue. The tissues about the vessels and immediately under the epidermis seem to be invaded earlier than other tissues. Bacteriological characters of the broad‐bean organism are described. A non‐pathogenic strain was found which corresponded in bacteriological characters with the pathogenic strains.