120 PROTECTION OF PLANTS — 1922-23 



DESCRIPTION OF PLATES. 



-The Iris plot at Macdonald College, showing misses due to plants 

 having been killed by the disease. 



-The cut surface of an Iris rhizome, showing diseased and healthy- 

 tissue. 



-Reverse side of Fig. 2 showing very little differentiation except the 

 collapsing of the root on the diseased part. 



-Photomicrograph of cross section of healthy rhizome tissue showing 

 the starch grains intact. 



-Cross section of diseased rhizome tissue showing the lack of starch 

 grains and also the bacteria within the cells. 



Plate VI. 



-The final stage in the disintegration of a diseased rhizome. 



-Section through a healthy leaf. 



-Section of a diseased leaf showing the death of the tissues due to 



the invasion of the pathogen. 

 -Diseased leaf tissue showing disorganization of cells and presence 



of bacteria. 

 -The final stage in the disintegration of the leaf tissue 



Plate Vn. 



-The complete death of a plant caused by the artificial inoculation 

 with B. Carotovorus. 



-One collapsed shoot of an infected plant showing the typical water- 

 soaking, a characteristic early symptom. 



-Here is shown the complete collapsing and typical watersoaking 

 of a plant inoculated while growing under absolutely sterile 

 conditions. 



Bibliography 



1. Cook, M. T.; The Pathology of Ornamental Plants Bot. Gaz. LXI; 67; 1916. 



2. Fred, E. B.; Soil Bacteriology. 1916. 



3. Harding, H. A.; Morse, W. J.; and Jones, L. R.; The Bacterial Soft Rots of certain Vege- 

 tables. N. Y. Geneva Tech. Bui. 11; 250-368; 1909. 



4. Harshberger, J. W.; Mycology and Plant Pathology. 1917. 



5. Howitt, J. E.; and Jones, D. H.: The More Important Fungous and Bacterial Diseases 

 of Vegetables in Ontario. Ont. Dept. of Agr., Bull. 258. 1918. 



6. Jones, L. R.; A Soft Rot of Carrot and other Vegetables. 13th. Ann. Rpt. Vt. Agr. Exp 

 Sta.; 299-332. 1900. 



7. Marshall, C. E.; Microbiology; 512; 1912. 



8. Smith, E. F.; Bacteria in Relation to Plant Diseases. I.; 180; 1905. 



9. Smith, E. F.; Bacterial Diseases of Plants; 239; 1920. 



10. Van Hall, C. J. J.; Originalabhandlungen. Das Faulen der junger Schosslinge und 

 Rhizome von Iris florentina und Iris germanica, verursacht durch Bacillus omnivorus V. Hall 

 und durch einige audere Bacterienarten; Zeit. fur. Pflanzenkrank; XIH; 28-144; 1903. 



