EFFECT OF SOIL TEMPERATURE ON BEAN PLANTS 
with the temperature. In one instance, at the end of five days, the 
diameters of the thalH in milhmeters for the stated temperatures are 
shown in the accompanying table. 
Table I 
Diameters in Millimeters of Thalli of Fusarium martii phaseoli when Grown for Five 
Days at the Temperatures Indicated 
Diameter of » 
Temperature ' Thallus * 
°C. Millimeters 
12-13 8 
15-16 12 
17-18 15 
19-21 17 
23-25 23 
26.5-27.5 28 
30-5-3I-5 34 
35-35-5 13 
38.5-39 No growth 
It appears from the table that the highest temperature selected for 
the experiment was one near, but perhaps slightly above, the optimum 
for the growth of this fungus, but it is to be noted that growth takes 
place at a temperature much below the lowest temperature selected 
and infection occurred on inoculated plants in the cultures at all three 
soil temperatures employed. 
It is unfortunate that a low temperature was not selected that 
would at least have permitted the growth of beans even though poorly. 
It is well known^ that beans require a warm soil for their best develop- 
ment. In a cold soil presumably bean plants would not have as great 
vitality and might have proved particularly susceptible to this hemi- 
parasite. Likewise, in the case of cabbage it is well known that the 
plants do well in a cool summer and poorly in a warm one. At the 
higher temperatures the plants may possess a lower degree of vitality 
and hence should be more susceptible to facultative parasites. This 
point Oilman passes over lightly in his work. 
Cornell University, 
Ithaca, New York. 
^ Reynolds, J. B. Temperature in relation to seed. Ont. Agr. Col. Rept. 
29 (1903): 9-1 1. 1904. 
Sevey, Glenn W. Bean Culture, p. 7. New York. 1914. 
