20 
February, 1918 
Ol)£ Slower (Brower 
Cornell Bulletin on Gladiolus Corm Diseases 
Reviewed By S. E. Spencer. 
[ IV rittcn expressly for 'The Flower Grower. ] 
Several years ago at the request of 
Mr. Arthur Cowee, the New York 
Legislature appropriated a special fund 
of two thousand dollars and placed it 
at the disposal of the department of 
plant pathology of Cornell University 
Agricultural Experiment Station for 
the purpose of investigating Gladiolus 
diseases, and last September bulletin, 
380, was issued entitled “The Hard 
Rot Disease of Gladiolus.” 
In this pamphlet of about 30 pages, 
Mr. L. M. Massey tells the story of a 
long series of experiments conducted 
first at the University and later during 
the summer at Meadowvale Farm, 
Berlin, N. Y., for the purpose of dis- 
covering the cause of the disease and 
if possible finding a way to control and 
cure it. 
For some years, owing to the im- 
portation of diseased stock and the 
sale and exchange of bulbs among 
growers, the hard rot disease had been 
spreading until the loss was in the 
aggregate very large, in some individ- 
ual cases running as high as 25 to 50 
per cent. Many of the remaining corms 
while apparently sound and healthy 
were slightly diseased and if planted 
reproduced only weak, undersized and 
diseased stock. 
Several prominent students of fungus 
diseases had been consulted but were 
unable to explain the cause or suggest 
a remedy. 
Some growers advised treating the 
bulbs with solutions of various kinds; 
some used lime or sulphur at planting 
time, but because they had no accurate 
knowledge of the nature of the disease 
and the method of infection and did 
not use accurate and scientific methods 
in making experiments, all efforts were 
useless and the disease continued to 
spread. 
The first important fact established 
by Mr. Massey is that a leaf blight 
which sometimes develops on the 
foliage of seedlings and bulblet stock 
is one stage of the hard rot disease. This 
blight which rarely appears on the 
foliage of large bulbs, is indicated by 
small dark spots which gradually spread 
till they form rings of reddish brown 
or almost black, with light gray cen- 
ters. Later on these centers may drop 
out producing a " shot hole appear- 
ance.” [This should not be mistaken 
for a similar leaf blight which affects 
large plants, and is caused by the bite 
of the tarnished plant bug. The re- 
sulting discoloration is dark in the 
center with a light colored ring. It is 
not a disease but is injurious to the 
bulb in proportion to the amount of 
leaf surface destroyed.] 
" The hard rot disease of the Gladi- 
olus is caused by the fungus pathogene 
Septoria Gladioli Passer. Passerini col- 
lected specimens of the leaf stage of 
the disease near Parma, Italy, in June, 
1874.” Mr. Massey has proved that 
spores from diseased foliage will in- 
fect bulbs, but it is also proven that 
these leaf spores are not necessary for 
the development of hard rot. '' The 
fungus does not grow directly from 
the old corm into the new one.” Where 
the leaf stage is not present, the nor- 
mal progress of the organism is from 
the black diseased spot on the bulb 
into the soil and then back into any 
near by corm. When a diseased corm 
is planted in the spring, moisture and 
warmth stimulate the growth of the 
fungus and small pieces or spores are 
pushed out into the soil where they 
may remain alive for at least four 
years. The new corm growing out of 
this diseased one may escape and de- 
velop a healthy plant, but the chances 
are three in four that it will be attacked 
by one or more of the young and 
sprightly Septorias, and 25 to 50 per 
cent of the bulbs grown in the next 
four years in soil so infected will also 
be attacked. 
When these corms are dug in the 
fall they may not show any outward 
signs of disease but if the husk is 
stripped oft we may find one or more 
dark watery spots usually on the lower 
half. If the bulbs are cured well and 
conditions are not favorable to the de- 
velopment of the disease these spots 
will dry up, a callous will form around 
them and the black portion may be 
picked out. 
. But it frequently happens that the 
disease develops rapidly while in the 
ground and after digging, so that when 
we clean and sort the corms it is easy 
to pick out some that are badly af- 
fected. These should be burned at 
once. 
Other corms, as mentioned above, 
may have under the husk small dark 
spots where Septoria has found a 
home and is growing in the cellular 
tissue. Under favorable conditions the 
brown spots increase in size, the center 
becomes hard and black and if numer- 
ous enough the lesions run together 
till by spring a considerable part and 
perhaps all the body of the corm is 
dry, hard and dead. This condition 
can always be detected by the looseness 
of the husk. But in case the lesions 
are few and small there may be nothing 
to indicate disease unless the husk is 
stripped off and the corm is likely to 
be planted the following spring and 
the process of growth and soil infection 
is repeated. 
Now the important question arises, 
how can this troublesome disease be 
controlled and cured ? Mr. Massey has 
proved by a long series of experiments 
that healthy corms may be planted 
year after year in soil free from infec- 
tion and remain perfectly healthy ; 
and healthy corms planted where dis- 
eased corms have been grown will pro- 
duce a large per cent of diseased bulbs. 
No treatment has been discovered 
which will prevent infection or kill the 
organism in the diseased tissue without 
injury to the corm. Formalin and cor- 
rosive sublimate in solution, formalde- 
hyde gas, hot water and hot air have 
all been tried without success. 
Various chemicals, lime, sulphur, 
acid phosphate and soot have been ap- 
plied at planting without benefit. 
Diseased corms and foliage, roots 
and rubbish from a crop that is in any 
way infected should be either burned 
or composted and used at some dis- 
tance from the Gladiolus field. Leaf 
blight in seedling and bulblet stock 
may be controlled by spraying with 
bordeaux mixture to which has been 
added a small quantity of resin and 
sal soda crystals dissolved in water to 
cause the spray to stick to the foliage. 
All growers should continue experi- 
ments along this line until some chemi- 
cal or special treatment is discovered 
which will prove to be a sure and safe 
remedy. 
Mr. Massey concludes that " Select- 
ing healthy corms and growing them in 
soil free of pathogenes is the only 
means known that will give an abso- 
lutely healthy crop.” 
To growers with a limited acreage 
he suggests the selection of as many 
healthy corms as possible, planting 
them in clean soil. The second year 
add more healthy stock and so gradu- 
ally work away from diseased stock 
and infected fields. 
We owe a debt of gratitude to the 
State of New York and its Agricultural 
Experiment Station for the generous 
way in which they provided for this 
investigation ; to Mr. Massey and his 
co-workers, Prof. Whetzel, Dr. Red- 
dick and others, for the thoroughness 
with which they worked out every de- 
tail ; and to Mr. Arthur Cowee who 
first suggested the appropriation and 
then gave the use of fields for exten- 
sive plantings and his studio for use as 
a laboratory. 
Note by the Editor— 
Mr. Spencer has promised us in ad- 
dition to his careful review of the Cor- 
nell Bulletin above referred to, that he 
will also review Cornell Bulletins Nos. 
9, 10 and 11, Gladiolus Studies Nos. I, II 
and III, by A. C. Beal and Alfred C. 
Hottes. The idea is to put the infor- 
mation in condensed form so that those 
who have not the bulletins available, 
may at least get a summary of the in- 
formation in the form of Mr. Spencer’s 
outline or review. 
A. E. Kunderd, Goshen, Ind., will 
make an attractive prize offer for the 
best display of the Kunderd varieties 
of Gladioli at the next flower show of 
the Massachusetts Horticultural So- 
ciety next summer as follows : 
For the largest and best collection of the 
Kunderd varieties of Gladioli : First prize, a 
Gold Medal. Second prize, 100 corms of the 
variety, Mrs. Frank Pendleton. Third prize, 
50 corms of the same variety. Fourth prize, 
25 corms of the same variety. Second largest 
collection may secure first award if quality 
of bloom justifies it. 
