The answer to the problem of Fu- 
sarium in glads is to grow disease- 
free planting stocks, as demonstrat- 
ed so well in the potato industry 
which had a similar problem 25 years 
ago. Glad growers have been propa- 
gating “table stock” (potatoes fit for 
eating but no good for planting). 
They must begin to segregate and 
build up disease-free propagating 
stocks. If cormels from disease-free 
stock can not be obtained, it would 
be desirable then to grow the va- 
riety fer a few years in western 
Washington. As it is now, the best 
commercial varieties, such as Spic 
and Span, are being propagated from 
any and all stocks regardless of dis- 
ease content. Before it is too late, 
Fusarium-free stocks of all worth- 
while varieties, including new ones 
as they are released, should be iso- 
lated and carefully maintained. This 
might be done best by growers who 
specialize in supplying propagating 
stocks. 
Virus, Too 
Undoubtedly certain areas of the 
country will be found most suitable 
for the purpose, because of the 
greater ease of keeping stocks free 
of viruses also in those locations. 
Viruses and virus-like diseases of 
glads have been discussed in previ- 
ous numbers of this publication by 
Dr. Philip Brierly of the Plant In- 
dustry Station, Beltsville, Md. It is 
sufficient to say here that it would 
be foolish to set up a program of 
supplying Fusarium-free corms and 
not keep the stocks free of virus 
diseases, too. Although corms can be 
maintained free of Fusarium in al- 
most any region of the country, the 
growing of virus-free stock will be 
definitely limited to areas where 
isolation from other host plants and/ 
or freedom from insects that trans- 
mit the viruses are possible. 
Production Method 
The rapidity with which gladiolus 
may be propagated makes this pro- 
gram entirely practical. To begin, a 
large stock of a variety would not 
be necessary. A few quarts of cor- 
mels would be enough in some cas- 
es. Once obtained, a Fusarium-free 
stock can be maintained in a healthy 
condition for years by always plant- 
ing on clean soil, treating with Sper- 
gon dust as soon as the corms are 
broken from the mother corms, and 
keeping them separate from diseas- 
ed stocks. Workers or machinery 
used on diseased stock should not 
be used on the propagating stocks. It 
would be best to keep diseased 
stocks off the farm entirely. 
Maximum cormel production may 
be obtained by planting shallow, ir- 
rigating so as to maintain uniform 
moisture and good aeration of soil, 
and by spraying to control diseases 
and insects. Someone who recogniz- 
es the symptoms of virus-like dis- 
eases and corm rots should rogue the 
plantings at least three times while 
in leaf, removing diseased or ‘ab- 
normal plants, corm and all. 
If virus infection is found, allow 
the spikes to open in the field and 
inspect twice weekly to remove in- 
fected plants. Save cormels only 
from healthy - appearing corms. 
Corms bearing less than the average 
number of cormels, those having a 
dull appearance, and those which 
do not break from the mother corm 
cleanly should be discarded along 
with the cormels because such corms 
may carry Fusarium. Dust the corms 
with Spergon or Spergon (wettable) 
immediately after cleaning off the 
old corm. 
Summary of Experience 
In summation, it can be said that 
all commercial varieties are grad- 
ually picking up Fusarium infection. 
The disease can be controlled only 
by building up disease-free propa- 
gating stocks to serve as a reservoir 
to replace flowering corms as they 
pick up disease. Experience indi- 
cates that in Florida replacement of 
Picardy would be necessary every 
four to five years, provided the land 
is planted to glads no oftener than 
eyery third year and if the infections 
are controlled at cleaning time. It 
would probably be good economy to 
replace the stocks as soon as the loss 
to the disease from a planting 
reaches 15 to 20 per cent, because, 
the loss will usually be high enough 
—Reprinted from SOUTHERN FLORIST AND NURSERYMAN, October 6, 1950 issue 
the following year to preclude all 
chance for profit from the crop. 
To try to clean up a Fusarium- 
infested stock on the average farm 
is an expensive undertaking, and 
there is grave risk that it will be un- 
successful in the end. Attempts to 
develop disease-free stocks have 
failed in most areas because the in- 
fection is often latent; because in- 
fections spread rapidly when corms 
are cleaned, or injured in any way; 
and because roguing of diseased 
plants in the field must be done fre- 
quently and thoroughly. 
The fact that a stock of corms ap- 
pears to be healthy in Michigan, 
New York, Oregon or elsewhere 
does not indicate that the corms do 
not carry the Fusarium fungus. Lat- 
ent infections are commonly found 
in corms from these states. Planting 
corms in the warm soils of Florida 
tends to activate these infections. An 
effective program of maintaining 
disease-free corm stocks would have 
to recognize this fact. Growers in 
cooler regions could arrange to have 
their stocks sampled. and tested in 
warmer soils where Fusarium is 
very severe. A test farm in the west- 
ern part of the country, as well as 
one near the East Coast, could be 
supported by fees. 
The glad industry should be cau- 
tioned not to rely on certification 
(as we know it) to solve the prob- 
lem of controlling Fusarium. For 
one thing, inspection can not de- 
termine the presence of latent in- 
fection. Since most systems of cer- 
tification offer an incentive and 
loopholes for circumventing their 
purposes, it is believed our goal of 
healthy corms will be attained best 
by co-operative efforts between the 
different parts of the industry. 
In matters of this nature, the de- 
sire of a bulb grower to build and 
maintain a reputation and the de- 
sire of the flower grower to buy 
healthy corms from a_ reputable 
grower are the most effective influ- 
ences, provided the bulb grower is 
given the technical help necessary 
to do a good job. 
* Dr Magie later corrected this sentence to read: " At any reasoneble price,’ 
disease-free stocks ere certainly the least expensive for any grower. 
Because 
disease-free, corms of some commercial varieties are not generally aveilable 
from bulb growers." 
