ILLUSTRATIONS. 



PLATES. 



Page. 

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

 1 1 . Apples affected with bitter rot. Inoculation from a diseased apple. . 54 



III. 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 livingapple 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 J ' 



4. Berkeley's grape-rot fungus {Seploria rufu-maculans Berk. ) 26 



5. Berkeley's apple-rot fungus ( Gkeotyorium fruciigenum Berk. ) 27 



6. Diagrammatic cross section of an apple canker 32 



7. How to cut off a large limb ° 9 



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



9. Arrangement of vats used in making Bordeaux mixture 43 



8 



