372 
Journal of Agricultural Research 
Vol. V, No. 9 
Table II .—Spore and ascus measurements of the brown-rot fungus as given by various 
investigators —Continued 
FROM AMERICAN SOURCES 
Fungus and investigator. 
Host. 
Chlamydospores. 
Asci. 
Ascospores. 
Sclerotinia fructigena: 
Norton . . . 
rf 
M 
45 to 60 by 
3 to 4 
89.3 to 
107.6 by 
5.9 to 6.8 
125 to 215 
by 7 to 10 
130 to 179 
by 9.2 to 
n -5 
M 
Aderhold and Ruhl¬ 
and (1905) 
Reade (1908). 
6.2 to 9.3 by 
3.1 to 4.6 
10 to 15 by 
5 to 8 
11.4 to 14.4 
by s to 7 
1 7 by 11. 
Pollock (1909). 
fPlum. 
[In culture. 
14.4 to 24 by 9.6 to 
14.4 
9.6 to 14.4 by 7.2 to 
10.8 
T A 1 bv 0.0 
Mathenv (1013). . . 
Peach. 
xzj../ uy y.y. 
135 to 190 
by 6.9 to 
10.5 
i35 to 173 
by 6.8 to 
10.8 
10.5 to 14.5 
by 5.2 to 
7*5 
9.3 to 14.2 
by s to 7.4 
Plum. 
.uwbuvuj \ -“-oz. 
SCLEROTINIA STAGE 
The apothedal stage of the local brown-rot fungus has been found in 
abundance in the University of Minnesota Experiment Station orchard 
during the last few springs. It appears during the blooming period of the 
plums. The ascospores showed the characteristic refractive globules 
which Aderhold and Ruhland (1905) pointed out as being one of the char¬ 
acters which make it possible to distinguish between S. dnerea and S. 
fructigena , the latter species containing none. 
Some doubt has existed in regard to the exact time required for the 
production of the perfect stage after the formation of the sclerotium or 
mummy. The field observations of Norton (1902) and others seem to 
indicate that the apothecia are formed the second spring after the rotting 
of the fruit—i. e., in approximately 18 months. Other investigators 
(Dandeno, 1908) have thought that they may be produced the spring 
following the rotting of the fruit. No experimental evidence has come 
to the notice of the writer which shows definitely the period required for 
the production of apothecia; therefore, the following experiment was 
performed. 
During the fall of 1913 two lots of mummied plums and one of apples 
were buried. Tot 1 consisted of 1 plum each of 16 varieties which had 
been rotted in the laboratory. These were buried on October 8, 1913, 
about % to 1 inch deep in a shallow box, which was then placed level with 
the ground on a shaded hillside. Lot 2 consisted of (A) 106 fruits from 
8 varieties of plums which had rotted in the field under field conditions 
during the fall of 1913, and (B) 30 mummies of 3 other varieties which 
