194 
Journal of Agricultural Research 
Vol. V t No. s 
Table III .—Results of the inoculations of different varieties of potatoes with original and 
reisolated strains of Fusarium vasinfectum 
Strain No. 
1855. 
3i67>i855. 
3263. 
3*43 
Variety of potato. 
[Netted Gem... v 
Idaho Rural. 
[People’s. 
[Idaho Rural. 
| Netted Gem. 
| Burbank. 
[ Pearl. 
[Green Mountain. 
.do. 
do. 
do. 
,do. 
do. 
do. 
Number of 
tubers. 
Incubation 
period. 
Average 
temperature. 
Percentage 
of tubers 
rotting. 
5 
Days. 
25 
°C. 
25-5 
0 
3 
25 
25-5 
33 
5 
25 
25* S 
IOO 
4 
51 
21 * 5 
0 
4 
51 
21. 5 
0 
4 
Si 
21- 5 
0 
4 
SI 
21 - 5 
75 
1 
41 
18.3 
0 
1 
41 
18. 9 
0 
10 
41 
23* 5 
So 
1 
51 
17.8 
0 
1 
51 
18. 4 
0 
9 
41 
23- 5 
10 
1 
24 
24. 6 
IOO 
>=»reisolation of. 
JEEEY-END ROT AND A TUBER DRY ROT CAUSED BY FUSARIUM RADICICOLA 
JELLY-END ROT 
“Jelly-end” is the very appropriate name applied by growers to 
potatoes affected with a field rot and a storage rot which annually cause 
serious losses in the delta lands of California and in the irrigated sections 
of Oregon and Idaho. 
Many of the tubers when dug show the characteristic soft rot at the 
stem end, the affected portion easily separating from the rest of the 
tuber (PL XVI, XVII). The rot proceeds uniformly until the whole 
tuber becomes a slimy mass within the entire skin. If allowed to dry 
out, the skin sometimes persists as a loose attachment at the stem end, 
or it may shrivel and wrinkle down on the affected part, in this stage 
suggesting dry rot. 
The jelly-end rot is not a new disease, but nothing has been done to 
establish the cause of the trouble. Orton (9, p. 5), discussing the wilt and 
dry end-rot of potatoes in California, says: “An early form of this 
Fusarium dry end-rot is frequently met with shortly after digging, and 
potatoes thus affected are known to buyers as ‘ jelly-ends. ’ ” Shear (13, 
p. 6) says: “A serious feature of this disease [wilt] is that it forms a 
means of entrance for other fungous and bacterial diseases of the tubers, 
such as ‘ jelly-end' and dry rot.” The examination of specimens from 
different localities indicates that jelly-end rots may be caused by several 
species of Fusarium. Wollenweber (21, p. 257-258, 264-265) isolated 
both F. orthoceras and F . radicicola , and of this disease he says in part 
(p. 265): 
In Watsonville, Cal., in October, 1913, the writer found up to 80 per cent of Burbank 
potatoes in a large acreage affected by this peculiar soft rot, which is quite different 
