FAMILY PSEUDOMONADACEAE 



157 



malic and succinic acids. Arabinose, 

 rhamnose, dulcitol, salicin, inulin, and 

 cellulose not utilized. 



Starch is hydrolyzed. 



Optimum temperature 28° to 32°C. 

 Maximum 37 °C. Minimum 5° to 7°C. 

 Thermal death point 53° to 55 °C. 



pH range for growth: pH 5.2 to 10.5. 

 Optimum pH 6 to 8. 



Strict aerobe. 



Distinctive characters : Cultural char- 

 acters the same or similar to Xantho- 

 monas juglandis. The two species do 

 not cross-infect. 



Source : 26 isolates from widely scat- 

 tered filbert orchards in Oregon and 

 Washington. 



Habitat: Pathogenic on filberts (Cory' 

 lus avellana and C. maxima). 



12. Xanthomonas cucurbitae (Bryan) 

 Dowson. {Bacterium cucurbitae Bryan, 

 Science, 63, 1926, 165; Bryan, Jour. Agr. 

 Res., 40, 1930, 389; Phytomonas cucur- 

 bitae Bergey et al., Manual, 3rd ed., 

 1930, 251 ; Pseudomonas cucurbitae Stapp, 

 Bot. Rev., 1, 1935, 408; Dowson, Cent. f. 

 Bakt., II Abt., 100, 1939, 190.) From L. 

 curczirbita, a gourd; M. L. Cucurbita, a 

 generic name. 



Rods : 0.45 to 0.6 by 0.5 to 1.3 microns. 

 Motile, usually with a single polar flagel- 

 lum. Gram-negative. 



Gelatin: Liquefied. 



Beef-agar slants: Growth moderate, 

 mustard yellow, undulating margins, 

 viscid to butyrous. 



Broth: Moderately turbid. Ring and 

 yellow sediment. 



Milk : Precipitation of casein and diges- 

 tion. Alkaline. 



Nitrites not produced from nitrates. 



Indole not formed. 



Hydrogen sulfide produced. 



Acid from glucose, galactose, fructo.se, 

 lactose, maltose, sucrose and glycerol. 

 No acid from mannitol. 



Starch is hydrolyzed. 



Optimum temperature 25° to 30 °C. 

 Maximum 35 °C. 



Optimum pH 6.5 to 7.0. Limits of 

 growth pH 5.8 to 9.0. 



Slight growth in 5 per cent salt. 



Aerobic. 



Source : Species first isolated from 

 squash. 



Habitat: Causes a leaf spot of squash 

 and related plants. 



13. Xanthomonas dieffenbachiae (Mc- 

 Culloch and Pironc) Dowson. {Phy- 

 tomonas dieffenbachiae McCulloch and 

 Pirone, Phytopath., 29, 1939, 962; Bac- 

 terium dieffenbachiae McCulloch and 

 Pirone, ibid.; Dowson, Trans. Brit. 

 Mycol. Soc, 26, 1943, 12.) From M. L. 

 Dieffenbachia, a generic name. 



Rods: 0.3 to 0.4 by 1.0 to 1.5 microns. 

 Motile with a single polar flagellum. 

 Capsules. Gram-negative. 



Gelatin: Liquefied. 



Beef-infusion peptone agar colonies: 

 Slow growing, circular, flat, smooth, 

 translucent. Butyrous. Massicot to 

 Naples yellow. 



Broth: Turbid. Yellow rim or slight 

 pellicle. 



Milk : Slow peptonization and forma- 

 tion of tyrosine crj^stals. Litmus re- 

 duced. 



Nitrites not formed from nitrateaft 



Indole not produced. 



Hydrogen sulfide produced. 



Acid from glucose, sucrose, lactose, 

 galactose, fructose and glycerol . Growth 

 but no acid in maltose and mannitol. 



Starch moderately hydrolyzed. 



Optimum temperature 30° to 31 °C. 

 Maximum 37° to 38 °C. Minimum 5°C. 



Aerobe. 



Source : Seven isolates from diseased 

 leaves of Dieffenbachia picta. 



Habitat : Pathogenic on Dieffenbachia 

 picta. Artificial infection of Dracaena 

 fragrans . 



14. Xanthomonas holcicola (Elliott) 

 Starr and Burkholder. {Bacterium hol- 

 cicola Elliott, Jour. Agr. Res., 40, 1930. 

 972; Phytomonas holcicola Bergey et al.. 

 Manual. 4th ed., 1934, 271; Pseudomonas 



