Oct. 1, 1925 
Sclerotinia Species Causing Decay of Vegetables 
607 
avoid the interference of algal growth on the surface of the sand and 
on the edges of the pots. These pots should be placed in rather 
strong diffused light. Those placed in the north and west windows 
of the laboratory have produced apothecia abundantly during the 
late winter and spring months. 
Although sclerotia have been planted in sand during practically 
every month of the year, by far the greatest number have germi¬ 
nated and produced normal apothecia during the months from 
January to April inclusive (Table III). Since the water was admin¬ 
istered artificially in all instances, this factor may be considered 
constant, thus leaving the variable factors of light and temperature 
to be determined. No way of sharply separating the influences of 
light and temperature has been found. Nevertheless, since sclerotia 
have been germinated in the dark when they were held at 18° to 22° C. 
during the unfavorable summer months and whereas they did not 
germinate in the dark at laboratory temperatures (22° to 30°) during 
this time, it seems safe to assume that temperature was the more 
important limiting factor. 
Table III .—Germination of sclerotia of Sclerotinia species in sand at laboratory 
temperature 
Sclerotinia libertiana 
Date of 
planting 
sclerotia 
Apothecia 
Source of culture 
Date of 
culture 
Date of 
germination 
Num¬ 
ber 
started 
Num¬ 
ber ma¬ 
tured 
Diame¬ 
ter 
Height 
above 
sand 
Bean_ 
Jan. 4,1922 
Oct. 5,1922 
Feb. 
2,1923 
6 
6 
Mm. 
3 
Mm. 
3 to 6 
Carrot... 
Aug. 9,1921 
Mar\ 9,1922 
Apr. 
4,1922 
3 
3 
1 to 3 
4 to 8 
Do_ 
July 14,1921 
July 1,1922 
_do_ 
Apr. 
Feb. 
10.1922 
10.1923 
3 
3 
3 to 5 
4 to 6 
Cauliflower_ 
Oct. 6,1922 
1 
1 
7 
10 
Celery_ 
Aug. 1,1921 
Jan. 30,1922 
Feb. 
20,1922 
15 
10 
2 to 6 
5 to 12 
Chicory__ 
Jan. 25,1922 
July 28,1921 
Oct. 6,1922 
Mar. 
15,1923 
4 
1 
2 
4 
Endive. __ _ 
Oct. 7,1922 
Nov. 
14,1922 
9 
2 
4 
5 
Lemon__ 
Oct. 10,1922 
‘ Nov. 14,1922 
Jan. 
30,1923 
15 
5 
4 to 6 
4 to 8 
Lettuce_i. 
June 15,1921 
Oct. 5,1922 
Feb. 
21,1923 
8 
7 
3 to 6 
5 
Do_ 
Direct from 
Feb. 2,1923 
Mar. 
5,1923 
69 
8 
5 to 13 
4 to 10 
Do_ 
host. 
June 2,1921 
Jan. 30,1922 
Feb. 
17,1922 
6 
3 
4 to 5 
4 to 6 
Parsnip.... 
July 28,1921 
Mar. 9,1922 
Apr. 
15,1922 
14 
12 
4 to 7 
6 to 8 
Salsify 
. do 
_do _ 
Apr. 22,1922 
May 12,1921 
6 
6 
3 to 6 
5 to 8 
Strawberry.. 
Oct. 8,1920 
Feb. 24,1921 
3 
1 
4 
5 
Sweet potato_ 
Apr. 1,1922 
Nov. 8,1922 
Jan. 
9,1923 
16 
3 
3 to 4 
5 to 7 
Do.... 
Direct from 
Dec. 28,1922 
Feb. 
7,1923 
88 
14 
3 to 5 
3 to 6 
Turnip_ 
host. 
June 12,1921 
Jan. 30,1922 
Feb. 
20,1922 
3 
3 
5 
5 to 8 
Sclerotinia intermedia 
Salsify--- 
Sept. 14,1920 
Apr. 10,1921 
Apr. 28,1921 
18 
10 
2 to 4 | 5 to 8 
i 
Continued warm weather seems detrimental to apothecial produc¬ 
tion, but apothecia will form when the temperatures alternate between 
night and day, providing the extremes are not too great. This is 
shown by the development of normal apothecia in the winter months 
of December, January, and February, when the day temperature 
ranged between 20° and 22° C. and the night temperature between 
13° and 18°. 
Experiments do not show that any definite time is necessary between 
the planting of sclerotia and their germination. Sclerotia planted in 
