ASPARAGUS RUST 
This disease is of European origin, and first appeared in America in 
several localities along the Atlantic seaboard about 1896. It rapidly 
appeared farther and farther west until by 1902 it had become an important 
factor in asparagus-growing in California. It is much more destructive 
in this country than in Europe. It is the most important disease of 
asparagus in America. 
SYMPTOMS 
Most rust diseases exhibit themselves in some form of hypoplastic 
or metaplastic effect. While the very first effect of the asparagus rust is 
‘probably hypoplastic in character, this rapidly passes over into a necrotic 
condition, the host-tissues being rather quickly killed. The signs and 
symptoms of rust diseases group themselves about certain distinct spore- 
producing stages of the pathogene. In the case of the asparagus rust there 
are three: the cluster-cup stage, the red rust stage and the black rust stage. 
All of these occur on asparagus. 
The cluster-cup stage. The disease in this stage affects only the stalks 
in the young condition shortly after they come up in the early spring. 
Examine the specimens provided and OBSERVE :— 
1. The oval-shaped, light-green patches on the canes near 
the base, covered with minute honey-colored pimples. These are the 
spermagonial fruit-bodies of the pathogene,—the pycnia. 
2. On the lesions as they grow older, larger ‘pustules arranged 
in concentric order within the lesions, especially definite in the older spots; 
averaging how many to a lesion? 
3. That finally these pustules break through the epidermis 
and appear as round cup-shaped bodies,—the aecia, exposing the yellow 
spore-mass within. 
This phase of the disease is usually to be found only on volunteer plants 
along roadsides and hedgerows, on plants in abandoned plantations 
and in young uncut piantations. Make -a DRAWING to show the lesion 
of the cluster-cup stage. 
The red rust stage. This usually appears early in the summer on the 
plants which are allowed to grow up after the cutting-season. In the 
specimens provided, OBSERVE :— 
4. The rusty brown linear pustules scattered very abundantly 
cover the stem, branches and even on the needles,—the uredinial sori or 
uredinia. 
5. Their size, number and arrangement on the surface; relation 
to the host-tissues. 
6. The dusty character of their contents. 
7. Any pathogenic effects exhibited by the tissues about the 
sori. 
Make a DRAWING of a diseased stem; also a DRAWING of a tiredinium 
as seen under the hand-lens. 
The black rust stage. This phase of the disease begins to develop 
in late summer on the same branches and needles along with the red rust 
stage. During the transition, affected plants take on a brown color 
which, however, soon gives place to a distinct black, as uredinial develop- 
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