80 A Bacterial Spot of Citni^ 



improvement in the sanitation of the orchard would certainly prove 

 beneficial, and it is intended to carry out spraying experiments during 

 the ensuing season. 



Botanical Labobatobies of the Union of 

 South Afbica, Pretoria. 



LITERATURE CITED. 



1. Besson, a. Pntcticul Bacteriology, Microbiology and Serum Therapi/. 1913. 



2. DoiDGE, E. M. A Spot Disease of Citrus Fruits. South African Fruit Grower, 



Sept. 1916, p. 43. 



3. DoiDGE, E. M. A Bacterial Spot of Citrus Fruit. Agricultural Journal of South 



Africa, Nov. 1915. 



4. Hasse, Claea H. Pseudomonas Citri, the Cause of Citrus Canker. Journal 



of Agricultural Research, vol. iv, No. i. April, 1915. 



5. RiDGWAY, R. Color Standards and Nomenclature. Washington, 1912. 



6. Smith, Clayton O. Black Pit of Lemon. Phytopathology, vol. in, No. vi, p. 277. 



7. Smith, ER^VIN F. Bacteria in relation to Plant Diseases, vol. i. AVashington, 



1905. 



8. Report of the College of Agriculture and the Agricultural Experiment Station of 



the University of California, from July, 1913, to June 30, 1914, p. 68 



EXPLANATION OF PLATES. 



All drawings were nutde ir'ith liie aid of the camera hirida. 



PLATE 



III. Lemons, natural infection from Simondium, C.P., (a) lemon with a single typical 

 spot, (b) the fruit on the right has been wounded by numerous scratches. 



I\'. Lemons, natural infection, from Simondium, {a) an early stage of infection, the 

 spots are still Ught coloured, {b) Numerous infections at and remote 

 from staUv coalesced to form irregular bodies. 



V. Lemons, artificial infection, pricked with sterile needle, then three of them atomised 



with suspension of a pure cultuie of B. citriinaculans; the fruit to the right 

 in (a) is a control pricked with a sterile needle only. 



VI. J^emons, artificial infection, ten days after inoculation, (a) inoculated by needle 



pricks, (b) with hypodermic syringe. 

 VII. Naartjes (a) artificially infected by needle pricks. {!>) natural inf<'(tion from 



Simondium. 

 VIII. (a) Navel oranges, natural infection from Simondium. 



(6) "Parson Brown" sec^dling orange, artificial infection. 

 IX. (n) Lemon twigs showing infections round leaf I)ases, and jjctioles of fallen 

 leaves. 

 (6) Small branch from orange showing the same characteristic discolorations. 

 (r) Ijcaves with bacterial sp(jt, these are apparently rare and associated with 

 tearing of tissues by thorns. 



