IDENTIFICATION OF CERTAIN SPECIES OF FUSARIUM 
ISOLATED FROM POTATO TUBERS IN MONTANA ‘ 
9 y H. E. Morris, Assistant Botanist and Bacteriologist, and Gracb B. Nutting, 
Assistant in Botany and Bacteriology, Montana Agricultural Experiment Station 
INTRODUCTION 
The econorric importance to this State of Fusarium wilt and various 
storage and field rots of potatoes has been recognized for several years. 
Between 1914 and 1918 isolations were made from affected tubers until 
nearly 100 cultures had been obtained. These isolations have been cul¬ 
tured on artificial media, being transferred about twice a year and kept 
in a refrigerator at about 10° C. 
The purpose of this paper is to record the taxonomic work on these 
various Fusarium cultures. No especial endeavor was made to connect 
any of these species with an ascigeral stage, and in all our work no cul¬ 
ture showed any form of growth suggesting such a stage. 
SOURCE OF material 
The tubers from which the isolations were made came from many dif¬ 
ferent localities in the State. In fact, practically all sections except the 
extreme northwestern are represented. The exact source of eadi cul¬ 
ture will be found in Table I. Of the 97 original isolations only 70 were 
used. 
There is little doubt that dryrot and Fusarium wilt are of large eco¬ 
nomic importance to all potato growers in the State. In 1917, this 
Station reported in the plant disease survey a loss of 4 per cent in the 
potato crop due to wilt and a loss of 3 per cent due to dr)Tot. The year 
1917 is considered a normal one. These figures therefore represent the 
average yearly loss due to potato diseases caused by species of Fusarium. 
This loss is fairly evenly distributed over the State. 
literature reviewed 
A great deal of work has been done and a number of papers have been 
written on Fusarium troubles of potatoes, but the viewpoint in nearly all 
of this work is economic. However, in reporting on the economic phase 
many of the authors include some taxonomic data, and for this reason 
the following reviews are given. Occasional comment on individual 
papers has been made, but this has not been done consistently throughout. 
For convenience the various papers are taken up in chronological order. 
Smith and Swingle (19) ^ found that there was always present in the 
darkened vascular bundles of tubers affected with wilt, which had not at 
that time been separated from dryrot, a fungus which on culturing they 
found to be a species of Fusarium. In order to determine the characters 
of this fungus they grew it on about 40 different media and under various 
temperature conditions. The bulletin gives in detail the results of these 
* Accepted for publication July 24,1922. 
» Reference is made by number (italic) to “ Literature cited," p. 363-364. 
Journal of Agricultural Research, 
Washington, D. C. 
adl 
( 339 ) 
Vol. XXIV. No. 4 
Apr. 25,1923 
Key No. Mont.-xo 
