A Dry Rot of the Irish Potato Tuber 
67 
to above as occurring "at practically every point." The present 
authors' observations of the past summer tend to substantiate 
this view. The same objections must be raised against all ex- 
periments in which wounded plants are planted in non-sterile 
soil. 
These experiments show quite conclusively » that Fasarium 
tuberivorum cannot cause a wilt of potato vines by attacking live 
stems, subterranean or aerial. In spite of the fact that no 
successful inoculation experiments producing such a wilt with a 
Fusarium have ever been reported, the literature is full of refer- 
ences to such inoculations. 
Most workers and reviewers have read inoculation experi- 
ments into Smith and Swingle's bulletin tho none are there 
reported. Most of the publications of the United States Depart- 
ment of Agriculture and the Experiment Stations dealing with 
the wilt of potatoes consider the causal connection of a Fusarium 
with a dry rot and wilt as established by this bulletin. These 
assumptions and statements have even crept into text-books. 
For example, Duggar 1909 (p. 317) says: "Smith and Swingle 
have by careful cultural and inoculation experiments demon- 
strated the causal connection of a Fusarium with these types of 
disease." In Germany the advocates of the fungus theory of the 
"Blattrollkrankheit" of the potato have gained most of their 
support from these assumptions.* 
During the early stages of our investigations of this disease 
we critically examined the description by Smith and Swingle of 
a "Dry Rot of Potato due to Fusarium oxysporum" to determine 
the relationship between the disease there described and the dry 
rot found in Nebraska. Since no reference to inoculation experi- 
ments could be found in their bulletin the senior author wrote 
Dr. Smith to learn where their inoculation experiments were 
recorded. Dr. Smith replied that no inoculation experiments 
whatsoever had been made by the authors. 
*Appel and Schlumberger 1911 ((pp. 22, 23): "Da endlich Smith und 
Swingle Impfversuche beschreiben, bei denen es ihnen gelungen ist, ein 
der Blattrollkrankheit ganz ahnliches Bild mit ihrem Fusarium oxy- 
sporum zu erzeugen, so lag die Erklarung, die Blattrollkrankheit ebenfall? 
auf ein Fusarium zuriickzufiihren, sehr nahe." 
Further, in a criticism of the enzym explanation of "Blattrollkrank- 
heit" entertained by Sorauer, they say (p. 28): "Wenn aber Sorauer 
sagt, dass alle Forscher einen anderen Pilz als Fusarium gefunden haben, 
so hat er dabei eine der wichtigsten Arbeiten iibersehen nahmlich die 
von Smith und Swingle (1904), die eine in ihren Erscheinungen der 
Blattrollkrankheit mindestens sehr ahnliche Krankheit auf Fusarium 
oxysporum zuruckfiihren." 
