14 
Colorado Experiment Station 
Plate IV. Pear affected with rust. The appearance of the disease on the apple fruit is 
similar. Note the long cylindrical-shaped bodies projecting from the surface, 
and woody, but in the spring may become swollen and gelatinous. 
Numerous finger-like gelatinous outgrowths are formed following 
a rain. Spores from the cedar apple infect the apple, causing the 
well-known rust upon it. 
Control .— (i) Where practicable, remove all cedars in the 
vicinitv of orchard. 
(2) Some varieties of apples are comparatively rust resistant, 
for example: Winesap, Grimes Golden, Yellow Transparent, Ben 
Davis, Red Astrachan, Duchess, and Maiden Blush. The following 
are most susceptible: Wealthy, Jonathan, Missouri Pippin, Whit¬ 
ney, and Red June. 
APRICOT. 
Black Knot.— See Plum, page 37. 
Crown Gall. —See Apple, page 12. 
ASPARAGUS. 
Rust. —Asparagus rust attacks the tall, branching plants that 
come up after the cutting season. The plant is hindered in its food¬ 
making process, and consequently the underground stems do not 
receive the normal amount of stored material. As a result, thev 
lack the strength to send up a good crop of “spears” the following 
spring. The rust appears as small lengthened spots on stems and 
leaves. The spots look like blisters at first, then they break open 
