638 



IVIANUAL OF DETERMINATIVE BACTERIOLOGY 



and CO 2. Produces a pellicle on the 

 inorganic liquid medium. 



Source: Calcareous soil. 



Habitat: Probably widely distributed 

 in soil. 



*4o. Bacteriiun stewartii Erw. Smith. 

 (Sweet corn bacillus, Stewart, N. Y. 

 Agr. Exp. Sta. Bui. 130, 1897, 423; 

 Pseudomo7ias stewarli Smith, Proc. A. A. 

 A. Sci., 47, 1898, 422; Smith, Pact, in 

 Rel. to Plant Dis., 3, 1914, 89; Aplano- 

 bacter stewarli McCulloch, Phytopath., 

 8, 1918, 440; Bacillus stewarli Holland, 

 Jour. Pact., 5, 1920, 220; PMjtomonas 

 stewartii Bergey et al., Manual, 1st ed., 

 1923, 192.) Named for F. C. Stewart, 

 American plant pathologist. 



Description from Smith, U. S. Dept. 

 Agric, Div. Veg. Phys. and Path., Bui. 

 28, 1901. 



Rods: 0.4 to 0.7 by 0.9 to 2.0 microns. 

 Capsules. Non-motile (McCulloch, loc. 

 cit.). Gram-negative. 



Gelatin: No liquefaction. 



Nutrient agar colonies: Small, round, 

 yellow colonies. 



Broth: Growth feeble with whitish 

 ring and j'ellow precipitate. 



Milk: Yellow ring but no visible action 

 on the milk. Slightly acid. 



Nitrites not produced from nitrates. 

 McNew (Phytopath., 28, 1938, 773) 

 states that less virulent strains assimi- 

 late only organic nitrogen; those of 

 intermediate virulence assimilate nitro- 

 gen from inorganic salts without reduc- 

 tion of nitrates to nitrites; virulent 

 strains reduce nitrates to nitrites. 



H3-drogen sulfide not formed. 



Indole production slight or none. 



Reduction of methylene blue in Dun- 

 ham's solution feeble or doubtful. 



Acid but no gas from glucose, galac- 

 tose, sucrose, mannitol and glycerol. 

 No acid from maltose. Acid from fruc- 

 tose, arabinose and xylose (McNew, 

 loc. cit.). 



Starch not hydrolyzed. 



Optimum temperature 30°C. Maxi- 

 mum 39°C. Minimum 8°C. 



Optimum pH 6.0 to 8.0. Limits about 

 pH 4.5 to 8.5. 



8 per cent salt restricts growth. 



Strict aerobe. 



Source: From wilted sweet corn. 



Habitat: Pathogenic on corn, Zea 

 mays. Sweet corn very susceptible 

 and field corn slightly so. 



46. Bacterium tardicrescens Mc- 

 Culloch. (McCulloch, Phytopath., 27, 

 1937, 135; Phytomonas tardicrescens 

 Burkholder, Phytopath., 27, 1937, 617.) 

 From Latin, slow growing. 



Rods: 0.6 to 0.8 by 1.58 microns. Mo- 

 tile with a polar flagellum. Gram-nega- 

 tive. 



Gelatin: No liquefaction. 



Beef-extract agar colonies: Circular, 

 mustard yellow, edges entire, 1 to 1.5 

 mm in diameter. 



Broth: Light clouding. 



Milk: Slightly alkaline. Clearing 

 after 5 to 6 weeks. 



Nitrites are produced from nitrates. 



Indole not produced. 



No HoS produced or feebly so. 



Acid but no gas from glucose, fructose, 

 galactose, arabinose, xylose and rham- 

 nose. Alkaline reaction from salts of 

 citric, malic and succinic acid. 



Starch is not hydrolyzed. 



Not lipolytic (Starr and Burkholder, 

 Phytopath., 32, 1942, 603). 



Optimum temperature 26°C. Maxi- 

 mum 32°C. Minimum 5°C (McCulloch, 

 Phytopath., 28, 1938, 648). 



Optimum pH 6.5 to 7.5. Growth slight 

 at 5.8 and 8.0 (McCulloch, loc. cit.). 



No growth with 3 per cent salt (Mc- 

 Culloch, loc. cit.). 



Aerobic. 



Distinctive character: Very slow 

 grower. 



*The section covering species of interest to plant pathologists has been pre- 

 pared by Prof. Walter H. Burkholder, Cornell Univ., Ithaca, New York, May, 1946. 



