July 15, 1924 
Botrytis Rot of the Globe Artichoke 
91 
CONTROL OF THE DISEASE 
Two lines of control suggest them¬ 
selves. The first and most effective, if 
it were possible, is prevention of con¬ 
tamination and, to a lesser extent, of 
primary infection in the field; the 
second is prevention of primary spore 
infection and of secondary contamina¬ 
tion and infection in transit. 
There was no opportunity for trial 
of protective sprays or dusts. In 
general, these have not been very suc¬ 
cessful in combating diseases caused by 
Botrytis sp. The greatest promise of 
control in the field lies in sanitary 
measures, such as the destruction of 
plant trash. Yet, even though scrupu¬ 
lous sanitation in the artichoke fields 
would very much lessen the amount of 
contamination, it would not necessarily 
eliminate Botrytis entirely, since coastal 
California weather conditions allow the 
fungus to grow saprophyticallv and 
parasitically on a great range of wild 
and cultivated plants. Maintenance 
of the low temperatures which can be 
obtained in the best refrigerator cars 
can not completely control the disease 
because even though low temperatures 
above the freezing point of the buds 
retard infection, development, and 
spread of the disease, they do not con¬ 
trol it completely, since the fungus can 
grow at temperatures low enough to 
injure and freeze the buds. More¬ 
over, low humidity controls primary 
spore infection as well as secondary 
contamination and infection much 
more than do low temperatures. In¬ 
fection by spores or by mycelium was 
not obtainable at any temperatures 
unless the buds were kept in a humid 
atmosphere. Unfortunately, equip¬ 
ment was not at hand to determine 
just what humidity is necessary for 
spore germination and for infection by 
spores and mycelium. Control of 
humidity in refrigerator cars at present 
is difficult, because the present method 
of cooling cars by melting ice inevitably 
leads to a humid atmosphere. 
Since these experiments show that 
even though spore germination and 
growth can take place at temperatures 
between —2° C. and 5°, and since in¬ 
fection by spores (the primary method of 
infection) does not take place at tem¬ 
peratures below 5°, much infection 
might be prevented if it were possible to 
get the buds cooled to this temperature 
immediately after cutting. Once in¬ 
fection has taken place, growth of the 
fungus and the infection by mycelium, 
for which wounds are not essential, 
can take place at temperatures ranging 
from —2° to 32°. Commercially sig¬ 
nificant lesions can develop in infected 
buds at 0° during the 10 to 15 days 
necessary to get the buds to eastern 
markets. Nevertheless, maintenance 
of a temperature of about 5° C. is de¬ 
sirable, as preventing secondary infec¬ 
tion by spores, retarding growth of the 
fungus, and lessening secondary infec¬ 
tion by mycelium. 
Though some tearing of the tips of 
scales takes place during growth and a 
large wound must be made when the 
buds are cut from the plants, more 
careful handling of the buds during 
harvesting and packing could eliminate 
a great deal of wounding. 
Control of the disease is therefore a 
complex problem, and responsibility 
for losses in transit or storage is divided 
among all those who handle the crop. 
Growers should keep fields and their 
environs free from plant trash. The 
packer should avoid packing buds 
which show discolorations and lesions, 
since there are indications that buds 
cut in badly infested fields are more 
heavily contaminated than those from 
clean fields. He should not mix badly 
contaminated and clean buds, should 
handle them with the greatest care to 
avoid wounding, and should pack with¬ 
out delay and cool them at once to 
about 5°. The carrier should provide 
the most rapid car movement possible, 
because each additional hour increases 
the chances of infection with the con¬ 
sequent danger of larger and more 
numerous lesions. He should also pro¬ 
vide a temperature of about 5° while 
the buds are in transit, and try to pre¬ 
vent saturation of the atmosphere in 
the car. It is of advantage to the 
dealer to receive this stock quickly. 
He should then keep it in fairly dry, 
refrigerated places if it must be held 
any length of time. 
SUMMARY 
1. A rot induced by a Botrytis of the 
cinerea type causes serious transit 
losses of shipments of Globe artichoke 
buds from California. Morphologi¬ 
cally, the Botrytis strains isolated from 
the artichoke (except culture No. 255 
from the interior of a frozen stem) 
seem to be identical with those generally 
obtained from other vegetables. Cross 
inoculation tests lend additional weight 
to the view that a Botrytis of the 
cinerea type is responsible for practi¬ 
cally all Botrytis rot of vegetables. 
2. Although disease is of practically 
no importance in the artichoke fields 
so far as quality and quantity of 
marketable buds are concerned, the 
fields are the original source of con- 
