July 21, 1923 
Bacterial Spot of Lima Bean 
MS 
CULTURAL CHARACTERS 
Unless otherwise specified, all cultures were incubated in the dark at 
about 25 0 C., a temperature very favorable for the organism. Color 
notations have been made in comparison with Ridgway’s Color Stand¬ 
ards. 4 In most cases acidity of the medium was determined by both 
Fuller’s scale and hydrogen-ion concentration. Phenolphthalein was 
used as an indicator in the determinations by the Fuller’s scale method. 
The different agar media were made according to E. F. Smith’s formulae 
(6) except that 1.8 per cent of bacto agar was used. 
AGAR POURED PLATES 
On +10 p otato agar colonies appeared in about 24 hours, and at the end ? 
of 4 days were about 4 to 5 mm. in diameter. They were creamy white, 
glistening, smooth, circular, entire, umbonate, and opaque. Old cultures 
become a pale olive-buff color. The surface was usually rugose, but 
may appear more or less smooth. The consistency was butyrous.. 
Buried colonies were lenticular. 
On -f10 nutrient agar colonies appeared in about 48 hours, and after 
4 days were 3 to 4 mm. in diameter. They were flat, circular, smooth, 
glistening, butyrous, opalescent, with faint gyrose to marmorated mark¬ 
ings. The margins were undulate. After 3 to 4 days the medium began 
to turn yellowish-green underneath the colonies, and the color gradually 
diffused out into the medium. Buried colonies were lenticular. 
agar stabs 
Stabs in +10 potato agar showed abundant surface growth, rather 
convex, glistening, and creamy white. After several days the growth 
may spread over three-fourths to almost the entire surface. Scanty 
growth developed along the line of stab for a short distance. There was 
no change in the medium. 
Stabs in +10 nutrient agar developed slightly less abundant growth 
than on potato agar and was flat, opalescent, and glistening. There was 
scant growth along line of stab for a short distance. The medium was 
greened. 
AGAR STROKES 
On + 10 potato agar the slant stroke cultures made an abundant, flat, 
echinulate, smooth, glistening, butyrous, opaque growth. The color 
was creamy white when young, but when 10 days old it was pale olive- 
buff by reflected light. The medium was unchanged. 
On +10 nutrient agar slants growth was slightly slower and less 
abundant than on potato agar. It was thinner and fluorescent. The 
surface was smooth and glistening. It was echinulate, translucent, 
and butyrous. \ rflifht putrefactive odor was produced. The medium 
was greened, and after about 10 days, the growth was about the same 
color as the medium. 
BLOOD-SERUM agar 
Stroke cultures on blood-serum agar gave abundant growth. The 
medium was browned and slowly liquefied. In small tubes containing 
about 5 cc. of the medium and kept at about 25 0 C. liquefaction was 
complete in 4 weeks. 
4 Ridgway, Robert, color standards and color nomenclature. 43 p-, 53 col. pi. Washington, 
D- C. 1912. 
48109—23 - 3 
