Nov. i, 1915 
Potato Tuber-Rots Caused by Fusarium Spp. 
203 
Table VI.— Results cf the inoculation of different varieties of potato tubers with certain 
species of Fusarium and other tuber-inhabiting organisms 
Species and strain No. 
Variety of potato. 
Number of 
tubers. 
Incubation 
period. 
Average 
temperature. 
Percentage 
of tubers 
rotting. 
Idaho Rural. 
A 
Days. 
51 
51 
51 
51 
5 r 
5 1 
5 1 
5 i 
41 
41 
41 
41 
25 
25 
25 
25 
25 
25 
20 
°C. 
21. 5 
21. 5 
21. 5 
21. < 
0 
Fusarium solani 
Netted Gem. 
A 
0 
176. 
Burbank. 
A 
0 
Pearl. 
A 
a 50 
0 
Idaho Rural. 
A 
21. K 
Fusarium mariii 
Netted Gem... 
A 
21. K 
0 
186. 
Burbank. 
A 
21.5 
21. ? 
0 
Pearl. 
A 
0 
[Idaho Rural. 
4 
21.5 
21. 5 
21. K 
0 
Fusarium monili - 
Netted Gem. 
4 
0 
forme 3321. 
Burbank. 
A 
0 
Pearl. 
A 
21. 5 
25* 5 
25- 5 
25- 5 
25- 5 
25.5 
25.5 
23. 0 
21. 5 
21. c 
0 
Verticillium albo - 
[Netted Gem. 
4 
0 
Idaho Rural. 
4 
0 
atrum 1717. 
People's. 
5 
4 
0 100 
Verticillium albo - 
atrum 2784. 
[Netted Gem. 
0 
Idaho Rural. 
7 
0 
People's. 
0 
s 
12 
a 60 
Sporotrichum fla- 
vissimum 1455. 
Burbank. 
0 
[Idaho Rural. 
A 
Si 
Si 
SI 
51 
0 
Mucor sp. 3320- 
J Netted Gem. 
A 
a 25 
0 
A 1 
21. 5 
21. 5 
[Pearl. 
A 
a 25 
a The respective organism is doubtfully the cause, as in each case wound-parasitic species of Fusarium 
were isolated in association. See text. 
TAXONOMIC ARRANGEMENT AND DIAGNOSTIC CHARACTERS OF 
IMPORTANT ROT-PRODUCING SPECIES OF FUSARIUM 
FUSARIUM Link 
The sections Martiella, Elegans, and Discolor provisionally estab¬ 
lished by Wollenweber (19, p. 32; 20, p. 28) include the species of Fusa¬ 
rium causing tuber-rot known to be economically important. Certain 
other species—namely, F. ventricosum , F. gibbosum, F. culmorum, 
F. orthocems , and F. subulatum —reported by Wollenweber (19, 20) as 
weak wound parasites of the Irish potato are not included in the fol¬ 
lowing arrangement of species. F. solani , the type species of the section 
Martiella, is listed because of its ubiquitous occurrence on potatoes as 
well as on roots and- tubers of other plants. Subnormal conidia of F . 
coeruleum , F. radicicola , and F. eumartii are easily confused with those 
of F. solani . The form, size, and septation of normal conidia must be 
depended upon for differentiation. 
