Dec. 8,1923 
Fusarium Stem and Rootrot of Peas 
473 
tive collections from other States. A large majority of cultures obtained 
were species of Fusarium which upon classification were found to consist 
of five or six species in almost equal numbers, any one of which was 
obtained as frequently as the parasite previously described. From this 
collection the following species were selected for thorough trial of patho¬ 
genicity, some because of the frequency of their occurrence, and others 
because of previous mention in literature as parasites: Fusarium oxy- 
sporum Schlecht., F. solani Mart., F. sclerotioides Sherb., F. vasinfectum 
Atk., F. redolens Wr. 
Fusarium oxysporum Schlecht.—This species was given a most thor¬ 
ough trial, not only in the field, but in soil held at the entire range of 
temperatures used in the experiments previously noted. In all cases the 
plants remained as healthy as the controls. No evidence of parasitism 
was obtained. 
Fusarium solani Mart.—Cultures of this fungus were obtained more 
frequently in early spring. After unsuccessful attempts to produce 
infection at greenhouse temperatures, sterile soil was inoculated with 
the fungus and held at 14°, 18 0 , 22 0 , and 26° C. At 18 0 C., 6 plants out 
of 9 showed a slight superficial browning of the base of the stem. At 
22 0 C., 8 plants among 10 showed a similar browning but deeper. The 
fungus was recovered from these lesions. At 26° C. the stems were not 
injured, but a considerable number of dead rootlets were found. Thus 
this fungus can be regarded as a very weak parasite at a temperature 
somewhat lower than that required by the other species tried, but 
probably not of economic consequence. 
Fusarium sclerotioides Sherb.—Although this fungus was isolated 
more frequently than any other, inoculations in greenhouse and field from 
cultures obtained during the first summer of work gave no positive indi¬ 
cations of pathogenicity. A heavy inoculation of soil with spores from a 
culture obtained the following year produced a wilt in three plants when 
the soil was held at 27 0 C., 25 days after planting. The fungus was 
reisolated from the discolored vascular strands. Ten out of 16 remain¬ 
ing plants at this temperature showed discoloration of base of stem, and 
much bronzing of small roots. When peas were replanted in this soil 
the resulting injury was much less. Thus, although this fungus can 
be a parasite under conditions favorable for infection, it does not 
appear that it is ever an important parasite under field conditions. 
Fusarium vasinfectum Atk.—The variety odoratum was found among 
the cultures, but was not used in making inoculations. In a series par¬ 
allel with that described for F. solani no infection was obtained. Field 
inoculations gave no evidence of infection. The evidence does not 
indicate that this fungus can gain unaided entrance to the vascular 
bundles where it is so often found. 
Fusarium redolens Wr.—Although this fungus has been mentioned 
by Wollenweber as a vascular parasite of peas, the two cultures obtained 
by the writer gave no more than a trace of infection from which the 
fungus could not be reisolated. 
Among all the cultures of Fusarium obtained from peas, no cultures of 
the Fusarium falcatum reputed to be the cause of the St. John’s disease 
in Holland, or of the F. viticola found by Turesson in Sweden were 
obtained. A culture of F. falcatum obtained from another source gave 
no infection. The only species of this genus that has been found able 
to enter an uninjured pea plant to produce appreciable damage is the 
