34 
COLOKAIH) ExPEHIMENT StATION 
lum) (26) — see Peach. Crown-Gall (Pseudomonas tumefaciens) (13) 
— see Apple. Frost Injury (17) — see Apple. 
ASPARAGUS 
Rust (Puccinia asparagi) (27), (28), (29), (30) — Asparagus rust 
was introduced into this country from Europe about twenty-five 
years ago. It spread rapidly over the entire country within a very 
few years and seriously threatened the asparagus crop where ever 
it appeared. 
Rust affects the tall branching plants that spring up after the 
cutting season in spring and summer. Numerous oblong orange red 
spots are found on the stems and leaf-like branches. These spots 
are pustules containing thousands of yellowish brown spores which 
are blown about by the wind to healthy plants. Whenever one of 
Asparagus rust. Summer stage. Asparagus rust. Winter stage. 
these spores fall on an asparagus plant under the proper* conditions 
of moisture and temi)eratui*e it germinates and penetrates the plant 
forming a new pustule of spoi*es. These may be produced in such 
abundance that the whole plant will take on a yellowish appearance 
and spoi*es will be blown in clouds for some distance by the wind. 
The rust saps the nourishment fi*om the plant and hinders it in 
its food making process. As a result of this the underground 
stems do not receive the noi*mal amount of stoi*ed material, con- 
secpiently they fail to send up a good crop of “spears” the tollow- 
ing year. 
The red or summer spores are short lived and cannot live over 
the winter. In September and October a ci’oi) of hai*dy black si)oi‘es 
