September, 1955 
ture range used was 20-22 degrees C., the 
minimum temperature for growth of these 
isolates was not determined. The range 
of temperatures for optimum growth of all 
six isolates was 26-28 degrees C. All iso- 
lates grew at 37 degrees C., but only vas- 
90 
80 
70 
60 
50 
40 
30 
20 
AVERAGE COLONY DIAMETER IN MILLIMETERS 
ForsperG: FusARIUM DISEASE OF GLADIOLUS 457 
cular isolate +5-73 and basal dry rot iso- 
late 50-23 showed traces of growth at 39 
degrees C. None of the isolates grew at 
40 degrees C. After the test period, all 
Petri dishes that had been incubated at 40 
degrees were kept at room temperature for 
Isolate 45-73 
Isolate 50-24 
J jell | 
(0) 5 10 15 
25 30 Soke 40 
TEMPERATURE, DEGREES CENTIGRADE 
Fig. 6.—Effect of temperature on the colony size of two vascular isolates of Fusarium grown 
160 hours on Coons’s agar. 
90 
80 
70 
60 
50 
40 
30 
20 
AVERAGE COLONY DIAMETER IN MILLIMETERS 
(0) 5 10 15 
x Isolate 50-22 
e 
\ 
\ 
\ Isolate 45-75 
a 
25 30 35 40 
TEMPERATURE, DEGREES CENTIGRADE 
Fig. 7.—Effect of temperature on the colony size of two brown rot isolates of Fusarium 
grown 160 hours on Coons’s agar. 
