J an. 26,1924 
A Bacterial Blight of Gladioli 229 
TECHNICAL DESCRIPTION 
Bacterium gummisudans, n. sp. 
A short rod, rounded at the ends, individual rods 1 to 2.8ju by 0.6 to o.Spi; motile 
by means of one polar flagellum 3 to gn long, capsules present, no spores; aerobic. 
A yellow, viscid growth is formed on culture media; nitrates are not reduced; casein 
in milk is digested; gelatin is liquefied; acid is formed from dextrose and saccharose; 
ammonia and hydrogen sulphid are produced; optimum temperature about 30° C., 
maximum 36°, minimum below 2 0 ; thermal death point near 50°. Sensitive to 
sodium chlorid and to acids; readily killed by drying and by exposure to sunlight. 
Gram-negative; not acid-fast. Group number 211.2322523. 
Pathogenic on leaves of gladioli forming more or less angular, translucent spots. 
Type specimens have been deposited in the herbarium of the Bureau of Plant 
Industry, United States Department of Agriculture. 
SUMMARY 
The bacterial disease described in this paper is capable of causing 
serious injury to the leaves of the gladiolus and consequently it inter¬ 
feres with the development of the conns. 
The lesions are more or less angular, translucent spots. From the 
infected tissues there is a rather copious and viscid exudate which when 
dry forms a thin, brittle layer, or small drops over the surface. The 
leaves are often coated with soil particles which have become embedded 
in the exudate. 
The bacteria are very abundant in the infected areas and pure cultures 
are easily isolated. On culture media this bacterium produces a yellow, 
viscid growth. It is motile, having one flagellum; capsules are present; 
no spores. It is Gram-negative and not acid-fast. The group number 
is 211.2322523. 
Numerous inoculations resulting in successful infections have proved 
that the bacterium isolated from the leaves is the cause of the disease. 
The organisms gain entrance to the tissues by way of the stomata. 
They invade the parenchyma and fill the intercellular spaces and cavities 
resulting from destruction of cell walls. 
