ILLUSTRATIONS. 



PLATES. 



Page. 



Plate I. Apples affected with bitter rot. Inoculation from a canker. . .Frontispiece. 



II. Apples affected with bitter rot. Inoculation from a diseased apple. . 54 



I II. Diseased apples under trees 54 



IV. The bitter-rot fungus on various fruits. Figs. 1, 3, and 7. — Various 



stages of growth on apples. Fig. 2. — An early stage of the disease 

 Fig. 4. — A mummified apple from the preceding year. Fig. 5.— 

 Growth of the bitter-rot fungus on a pear, with control fruit. Fig. 



6. — Growth of the bitter-rot fungus on squash 54 



V. Drawings showing various stages of the bitter-rot fungus. Fig. 1. — 

 Spores of the bitter-rot fungus ( Glomerella rufomaculans) growing 

 in pure culture. Fig. 2. — Germinating conidia of the fungus. Fig. 

 3. — Starch grains from diseased apple, showing corrosion. Fig. 

 4.— Resting spores of Glceosporium cactorum. Fig. 5. — Perithecia 

 of bitter-rot fungus from apple canker. Fig. 6. — Asci of the bitter- 

 rot fungus (Glomerella rufomaculans). Fig. 7. — Perithecium with 



asci from apple canker 54 



VI. Stages of growth of the bitter-rot fungus. Fig. 1. — Plate culture of 

 the bitter-rot fungus (Glomerella rufomaculans), showing masses of 

 perithecia. Fig. 2. — Enlarged group of pustules on an apple 

 affected with the bitter rot, showing the tendril-like spore masses. 

 Fig 3. — Apple diseased with bitter rot. The infection was made 

 with spores from a pure culture obtained from a canker. Fig. 4. — 



Control fruit ^ 54 



VII. Three limbs with bitter-rot cankers from living apple trees 54 



VIII. Cankers on living apple limbs. Fig. 1. — Cross section of four cankers. 



Figs. 2, 3, and 4. — Cankers on living apple limbs 54 



IX. Artificial cankers produced on living apple limbs by inoculating 

 spores of Glomerella rufomaculans into bark slits. Fig. 5 is an 

 enlarged view of fig. 4 54 



TEXT FIGURES. 



Fig. 1. Map showing geographical distribution of bitter rot 13 



2. Diagram showing how the bitter-rot fungus decays an apple 17 



3. A later stage of bitter-rot decay 17 



4. Berkeley's grape-rot fungus (Septoria rufo-maculans Berk. ) 26 



5. Berkeley's apple-rot fungus ( Glceosporium fructigenum Berk. ) 27 



6. Diagrammatic cross section of an apple canker 32 



7. How to cut off a large limb 39 



8. Method of cutting large limb which should be avoided 39 



9. Arrangement of vats used in making Bordeaux mixture 43 



