HARD ROT OF GLADIOLI 
This is one of the destructive diseases of gladioli. No varieties are 
known to be immune to it. The disease appears to occur wherever galdioli 
are grown. So far as known it affects only this host. 
SYMPTOMS 
Both foliage and corms may be affected. Although it rarely affects 
the foliage of flowering-sized plants, the disease occurs very commonly 
on leaves of plants the first year from seed and cormels. 
On the leaves. Examine the material provided. oBSERVE:— 
1. That the affected leaves show more or less circular reddish 
brown spots. 
2. The several zones of color in the lesions. 
3. That the spots usually extend from the edge to the midrib, 
although sometimes the lesion involves the entire width of the leaf. When 
this is the case, that part of the leaf above the lesion soon dies. 
4. That frequently two or more spots coalesce forming a large, 
more or less irregular lesion. 
5. That the spots show black bodies,—the fruit-bodies (pycni- 
dia) of the fungus. 
DRAW an affected leaf showing the several points above indicated. 
On the corms. When gladiolus corms are dug ip the autumn the lesions 
are usually very small. The disease develops during storage until by 
spring many corms are reduced to hard mummies. , 
Study the diseased corms provided. OBSERVE :— 
6. Size, shape and position of the lesions. Is it possible to 
determine whether or not a corm is diseased without removing the husk 
(sheathing leaf-base) ? 
7. That the center of the lesion is sunken; to what due? 
8. The black water-soaked margin separating diseased from 
healthy tissue. When the disease is not vigorously advancing, this margin 
is absent. 
9. That in old lesions the diseased tissue can be readily chipped 
out with the finger-nail. Cut through a lesion and oBSERVE:— 
10. The hardness of the diseased tissue. 
11. The depth of the lesion. 
Make such DRAWINGS as are necessary to bring out the above points. 
ETIOLOGY 
The cause of this disease is a fungous pathogene, Septoria Gladioli 
Passerini. 
Life-history. The complete life-history of this organism has not 
been definitely worked out. 
Primary Cycles. Just how these are initiated is not clear as the follow- 
ing statements indicate. The corms are lifted in the autumn, stored and 
set out the following spring. The fungus continues as an active parasite 
during the winter and is carried to the soil along with the corm. If the 
corm is not too badly affected it will sprout, sending up a shoot and produce 
a corm above with side clusters of cormels. Since in the large majority 
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