. The fungi which cause plant disease . Plant diseases; Fungi. 34 THE FUNGI WHICH CAUSE PLANT DISEASE From swellings known as olive tubercles on Califomian olive branches, E. F. Smith isolated this organism*' which is in part Ps. oleae-tuberculosis and which may bear relation to several other olive bacteria previously described in Europe. The organism when inoculated by puncture into young olive shoots produced the characteristic tubercle. Later it was re- isolated from these artificially produced tubercles and used in a second series of inoculations which gave a second crop of tubercles. Cont
. The fungi which cause plant disease . Plant diseases; Fungi. 34 THE FUNGI WHICH CAUSE PLANT DISEASE From swellings known as olive tubercles on Califomian olive branches, E. F. Smith isolated this organism*' which is in part Ps. oleae-tuberculosis and which may bear relation to several other olive bacteria previously described in Europe. The organism when inoculated by puncture into young olive shoots produced the characteristic tubercle. Later it was re- isolated from these artificially produced tubercles and used in a second series of inoculations which gave a second crop of tubercles. Controls showed no infection and healed promptly. The oleander was not susceptible to infection. Smith's results are not in full accord with much of the European work on the olive tubercle. Ps. sesami Malk. causes disease on sesame ^. Ps. stewarti, E. F. Sm. A medium size rod, - ju x 1 - 2 fi, with rounded ends, and 1 polar fiagellum. Buff-yellow to chrome or ochre color; non-liquefying; does not separate casein in milk. T. D. P. 10 min., 53°. Agar colonies subcir- cular, becoming lobate; bouillon rendered tur- bid with yellow-white precipitate. No gas. The bacterial com blight of this organism was first described by Stewart in 1897 " and attributed to bacteria. The organism was de- scribed by E. F. Smith in 1890«» from a cul- ture furnished by Stew- art. Definite proof by the causal relation of this particular organism to the disease was adduced in 1902 by sprinkling bacteria upon the ™ Some plants showed typical constitutional symptoms during the first month, most of them in two or three months when the plants were several feet. Fig. 21.—Various forms of Ps. stewarti, grown on potato agar; a and b are typical forms. After inoculation of. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original wo
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