Aug. 15, 1924 
Bacterium Marginatum on Gladioli 
177 
District of Columbia and near-by 
localities. This disease has been found 
on gladioli grown in Michigan, Ohio, 
Pennsylvania, Maryland, Virginia, Flor¬ 
ida, California, and Indiana. 
The leaf injuries vary from minute, 
reddish spots to large, brownish areas 
occurring most abundantly on the lower 
part of the leaves. The parenchyma 
is first destroyed and later the vessels 
become unable to supply sufficient 
moisture to the leaf which becomes 
brown and dry. 
Infected corms are more or less dis¬ 
figured by circular, shallow depressions. 
These are usually brown in color, horny 
or brittle in texture, and exude a gummy 
substance. The spots on the husks are 
brown to black, eventually disinte¬ 
grating and exposing the body of the 
corm. 
Isolations have been made from 
lesions on leaves, husks, corms, and 
from the exudate, and the patho¬ 
genicity of the bacteria from all these 
parts proved by inoculation experi¬ 
ments. 
Living, virulent bacteria have been 
isolated from corm lesions 9 months 
after being harvested. 
The organism causing these lesions 
is a medium-sized rod, having a 
capsule and one to several polar 
flagella. On beef media it forms a 
white, viscid growth. 
This organism grows best at tempera¬ 
tures between 25° and 30° C. (77-86° 
F.). Moisture, heat, and succulent 
tissues favor the progress of the 
disease. 
There is evidence that this organism 
remains alive in the soil in which 
diseased plants have grown. Crop 
rotation should be practiced. 
Control experiments have not yet 
been extensive enought to indicate 
the best methods for prevention, but 
considerable success has resulted from 
treating the corms with either mer¬ 
curic chloride (1-1,000) or formalin 
(1-80). 
LITERATURE CITED 
(1) McCulloch, L. 
1921. A BACTERIAL DISEASE OF 
gladiolus. Science 54: 115- 
116. 
( 2 ) - 
1924. TWO BACTERIAL DISEASES 
OF gladiolus. (Abstract) Phv- 
• topathology 14: 63-64. 
1924. A BACTERIAL BLIGHT OF 
gladioli. Jour. Agr. Research 
27: 225-230. 
(4) Massey, L. M. 
1916. THE HARD ROT DISEASE OF 
gladiolus. N. Y. Cornell Agr. 
Exp. Sta. Bui. 380, p. 149-181, 
illus. 
(5) Mizusawa, Y. 
1921. A BACTERIAL ROT DISEASE 
of saffrons. Bui. Kanagawa 
Pref. Agr. Exp. Sta. 51, 29 p., 
illus. [In Japanese. Eng. tr. 
in Ann. Phvtopath. Soc. Japan 
1: 1-12. 1923.] 
(6) Prillieux, E. E., and Delacroix, 
G. 
1894. MALADIES BACILL AIRES DE 
DIVERS VEGlDTAUX. Compt. 
Rend. Acad. Sci. [Paris] 118: 
668-671. 
(7) Ridgway, R. 
1912. COLOR STANDARDS AND COLOR 
NOMENCLATURE. 43 p., illus. 
Washington, D. C. 
(8) Rostrup, E. 
1887. SYGDOMME HOS KULTUR- 
planter. Tidsskr. Land0- 
konom. (V) 6: 463-485. 
(9 ) - 
1902. plantepatologi. 640 p., 
illus. K0benhaven. 
(10) Severini, G. 
1913. UNA BACTERIOSI DELL’iXIA 
MACULATA E DEL GLADIOLUS 
colvilli. Ann. Bot. Rome 11: 
413-424, illus. 
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1910. diseases of gladioli- 
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