86 
Journal of Agricultural Research 
Vol. XXIX, No. 2 
study, even though this product is less 
important than the majority of crops 
affected by the fungus. 
The work discussed in the present 
paper leads to the conclusion that, 
without previous or attendant freezing 
injury, a species of Botrytis, to be 
placed in the cinerea group, can pro¬ 
duce the condition responsible for the 
deterioration and consequent losses in 
transit. 
DESCRIPTION OF THE DISEASE 
The lesions which indicate the disease 
are so small and inconspicuous that 
they are often overlooked in harvesting 
and packing, the more so since they 
vary with external conditions. 
In the field the lesions are usually but 
1 to 2 mm. in diameter on actively 
growing buds of vigorous plants, and 
are generally restricted to the tips of 
the scales. They are sunken and 
brown to black. Sometimes buds 
severely affected by Botrytis are found 
on aging plants, or on vigorous plants 
after the close of the active period of 
bud production (October to May). 
These usually shrivel and wither, and 
are covered with sporulating mycelium. 
Extensive lesions of the moist type 
can be seen on vigorous plants in the 
field. They usually start in the wounds 
made when the buds are cut, whence 
they progress down the flower stalks 
and spread to the lateral branches 
and even to the main stems of the 
plants. 
The lesions may occur anywhere on 
the bud. Spore infection seems most 
frequent on the cut stem and at the 
tips of the scales which are generally 
somewhat split by growth tensions. 
Contact with the mycelium leads to 
infection of any part; under moist 
conditions the spider weblike growth 
of the mycelium starting from one 
original center of infection frequently 
involves the entire bud, the rot pro¬ 
gressing from scale tip to scale tip and 
down into the scale so that finally the 
entire bud is destroyed (pi. 1, A, B). 
Infection at the base of the scales or 
in the stem may destroy the entire 
stem and receptacle so that the bud 
readily falls apart (pi. 1, B). Under 
dry conditions, an affected bud then 
becomes a shriveled mummy. 
Under moist conditions the lesions 
on the buds have definite slightly 
water-soaked borders, semimoist to 
wet, odorless, reddish-brown to brown, 
and generally with abundant growth 
of sporulating mycelium on their older 
portions. Under drier conditions the 
advancing edge is not water-soaked, 
the affected tissues are dry and firm, 
brown to black, and show no aerial 
development. 
THE CAUSAL ORGANISM 
ITS ISOLATION AND IDENTITY 
Isolations of Botrytis sp. made from 
the flower buds of artichokes collected 
on the Chicago market, and from the 
stalks, stems and buds collected in the 
fields near Half Moon Bay, Calif., 
furnished the cultures used in the 
present study. A lot shipped from the 
fields was of particular interest because 
the entire plants including flower buds 
were frozen solid during transit. Viable 
cultures apparently identical with 
strains collected on the market were 
isolated from this material. One strain 
isolated from the interior of a frozen 
stem showing a brown surface lesion 
has maintained characteristics seeming 
to indicate a difference from all other 
cultures. On first isolation plates this 
culture, No. 255, grew more like a Fu- 
sarium than a Botrytis; but after one 
week’s growth sclerotia began to develop 
and conidia were observed around the 
edges of the plate. The cultures of this 
strain always produce a honey-yellow 5 
color in the substratum and fine ivory- 
yellow mycelium on potato-dextrose 
agar plates, as contrasted with the 
smoke-gray to light grayish-olive my¬ 
celium and grayish-olive substratum of 
the other strains. The gray strains 
also make greater vegetative growth 
and sporulate much more freely and 
abundantly than the yellowish strain. 
Morphologically, there do not seem 
to be great differences among the cul¬ 
tures under observation. The my¬ 
celium is pale smoke-colored at first, 
8 Ridgway, R. color standards and color nomenclature. 43 p., illus. Washington, D. C. 
1912. 
EXPLANATORY LEGEND FOR PLATE 1 
A. Artichoke held in a humid atmosphere, showing lesions and spider weblike growth of Botrytis myce 
lium over the surface. 
B—Longitudinal section through bud showing stem and receptacle infection. 
C.— Artichoke showing points of inoculation and lesions resulting therefrom. Mycelium was inoculated 
into wounds whose position is indicated by circles. Dark discolored areas show limits of fungus 
advance. The blotched discoloration on lower two scales is due to bruising. 
D .—Lesions and mycelium on split and wounded tips of scales resulting from inoculation with a spore 
suspension. 
