Jan. 22,1917 
Temperature Relations of Apple-Rot Fungi 
149 
at 2 5 0 ; PenicUlium expansum at 20°; and Neofabraea malic or ticis ati 5 0 . 
It is interesting to note that the highest summer temperatures are 
unfavorable to most of the vigorous rot organisms. The fact appears to 
explain numerous failures that the writers have had with fruit inoculations 
made in the hottest weeks of the summer. The graphs show that high 
Fig. 9.—Graph showing the development of 
the rot caused by Sderotinxa cinerea (apple) 
on Winesap apples. 
0 5 10 15 20 25 30 
Temperature (°Cent!grade) 
Fig. 10.—Graph showing the development 
erf the rot caused by Sderotinxa ctnerea 
(prune) on Winesap apples. 
temperatures had a greater retarding effect upon Neofabraea malicortieis 
than upon any of the other fungi. A further illustration of this was 
found in the removal of inoculated fruit from low temperatures to higher 
ones. When apples on which Sphaeropsis malorum , PenicUlium expansum f 
Fig. 11.—Graph showing the development 
of the rot caused by Sphaeropsis malorum 
on Yellow Newtown apples. 
Fig. 12.—Graph showing the development of 
the rot caused by Volutelia fructi on Yellow 
Newtown apples. 
and Neofabraea malicortieis had produced small rot areas at o° were 
removed to laboratory temperature (about 25 0 ), the first two fungi 
rotted the fruit all the more rapidly at the higher temperature, but 
the growth of the last named was apparently entirely checked. 
