Bean Anthracnose 



123 



minimum lies somewhere between 0° and 4° C, the optimum near 22°, 

 and the maximum between 34° and a few degrees lower. This corresponds 

 very closely to the observations of Edgerton (1915:254). The corn agar 

 permitted a little better growth than the potato agar. 



The growth at 4° C. was white, with considerable aerial mycelium 

 in most cultures. After four weeks a growth of from 25 to 35 millimeters 



Growth 

 inmm. 



0° 

 Fig. 12 



10° 



10 



22° 



28 



34° 



' 40° 



43° 



CURVE OF GROWTH OF TWO STRAINS, A AND B, OF COLLETOTRICHUM LINDEMUTHI- 

 ANUM AT VARYING TEMPERATURES 

 The light curves represent growth in potato agar, the heavy curves growth in corn agar. The clotted 

 lines represent average growth per day during the first six days; the straight lines, average growth per 

 day during the following eight days. The temperature is expressed in degrees centigrade 



was attained, and an olivaceous color, with spore production, was noticed 

 in a few agar and bean-pod cultures. Spores were produced in abundance 

 on bean pods at 10°, 16°, and 22° in six days, and but sparingly at 28°. 

 As already stated (page 121), bean pod cultures kept at 22° C. have 

 been found to give a rapid and abundant production of spores when the 

 fungus was in a spore-producing condition, in hundreds of cultures made 

 by the writer. 



