

optimum temperature of the growth- tempera ture graph also ap- 

 peared to move back from day to da:/ upon the temperature scale 

 "but not so rapidly as dirt the maximum for the earne correspond- 

 ing - periods. is tended in general to make the supra- optimal 

 slope of the curve for aac> 24-hcur period somewhat steeper 

 than fo 1 - the previous 24-hour period. In Phytcphthora there 

 was also a shifting- of the optimum, but this shifting was de- 

 finite from the data only between the first and second and be- 

 tween the fourth and fiftb 24-hour period. In Phomopsis there 



appeared to be a shifting of the optimum backward only between 

 the fourth and fifth 24-hcur period. 



6^ 



