158 



MANUAL OF DETERMINATIVE BACTERIOLOGY 



holcicola Stapp, Bot. Rev., 1, 1935, 407; 

 Starr and Burkholder, Phytopath., S2, 

 1942, 600.) From Gr. holcus, sorghum, 

 -cola, dweller; M. L. Holcus, a generic 

 name. 



Rods: 0.75 by 1.58 microns. Motile 

 with 1 or 2 polar flagella. Capsules. 

 Gram-negative. 



Gelatin: Liquefied. 



Beef-infusion peptone agar colonies : 

 Round, umbonate, glistening, smooth, 

 translucent to opaque, wax yellow, buty- 

 rous. 



Broth: Trace of growth in 24 hours. 

 Later turbid with a slight ring. 



Milk: Casein precipitated and pep- 

 tonized. Alkaline. 



Nitrite production doubtful. 



Indole not produced. 



Hydrogen sulfide is produced. 



Lipolytic (Starr and Burkholder, loc. 

 cit.). 



Acid, no gas, from sucrose. 



Starch is hj'drolyzed. 



Optimum temperature 28° to 30°C. 

 Maximum 36° to 37°C. Minimum 4°C. 



Optimum pH 7.0 to 7.5. Growth 

 range pH 5.5 to 9.0. 



Source : Isolated from many collections 

 of sorghum leaves showing a streak 

 disease. 



Habitat: Pathogenic on leaves of 

 Holcus sorghum and //. halepensis. 



15. Xanthomonas incanae (Kendrick 

 and Baker) Starr and Weiss. (Phyto- 

 monas incanae Kendrick and Baker, 

 California Bull. 665, 1942, 10; Starr and 

 Weiss, Phytopath., S3, 1943, 316.) From 

 its host plant Malthiola incana; L. 

 incanus, quite gray or hoary. 



Rods: 0.4 to 0.8 by 0.6 to 2.5 microns. 

 Motile with a polar flagellum. Gram- 

 negative. 



Gelatin : Liquefied. 



Beef extract agar colonies : Round, 

 smooth, convex or pulvinate, glistening, 

 margin entire, picric yellow to amber color. 



Broth: Turbid. 



Milk : No coagulation. A clearing of 

 the medium. 



Nitrites not produced from nitrates. 



Indole not formed. 



Lipolj^tic (Starr and Burkholder, Phy- 

 topath., 32, 1942, 600). 



Acid but no gas from glucose, lactose, 

 sucrose, mannitol, d-galactose, xj'lose, 

 d-mannose, raffinose, trehalose, and glyc- 

 erol. No acid from maltose, 1-arabinose, 

 or rhamnose. 



Starch not hydrolyzed. Starch hy- 

 drolyzed (Burkholder). 



Tolerates 3 per cent salt. 



Growth in beef broth at pH 4.4. 



Aerobic. 



Distinctive characters: Causes a dis- 

 ease of flowering stock but not of cabbage. 

 Differs from Xanthomonas campestris in 

 that it does not utilize 1-arabinose, nor 

 maltose. 



Source : Four isolates from diseased 

 plants of Matlhiola incana. 



Habitat : Pathogenic on flowering 

 stocks. 



16. Xanthomonas juglandis (Pierce) 

 Dowson. (Psetidomonas juglandis Pierce, 

 Bot. Gaz., 31, 1901, 272; Bacterium 

 juglandis Erw. Smith, Bacteria in Rela- 

 tion to Plant Dis., 1, 1905, 171; Bacillus 

 juglandis Holland, Jour. Bact., 5, 1920, 

 218; Phytomonas juglandis Bergey et al., 

 Manual, 3rd ed., 1930, 247; Dowson, 

 Cent. f. Bakt., II Abt., 100, 1939, 190.) 

 From L. juglans (-andis), the walnut; 

 M. L. Juglans, a generic name. 



Description taken from Miller et al., 

 Phytopath., 30, 1940, 731. 



Rods: 0.5 to 0.7 by 1.1 to 3.8 microns. 

 Motile with a polar flagellum. Capsules. 

 Gram-negative. 



Gelatin: Liquefaction. 



Nutrient glucose-agar streaks : Abun- 

 dant growth, filiform, convex, glistening, 

 smooth, opaque, pale lemon yellow, 

 viscid. 



Broth: Turbid. Ring formed in 2 to 

 5 days. 



Milk : Enzymatic curd that is slowly 

 digested. Litmus reduced. Crystal for- 

 mation (Burkholder). 



Nitrites not produced from nitrates. 



