3G 



Research Bulletin No. o 

 TABLE III— Continued 



These tables show a tendency of F. trichothecioides to make a 

 greater initial growth at low temperatures. At higher tempera- 

 tures, however, unless above the optimum of F. trichothecioides, 

 F. oxysporum, even though it made the greater initial growth, was 

 soon overtaken and passed by F. trichothecioides. This was espe- 

 cially marked when dextrose and levulose were used as carbon 

 source. This may be the result of a faster though more super- 

 ficial feeding of F. oxysporum, which makes it unable to use mate- 

 rials as thoroughly as the other organism. This phenomenon is hard- 

 ly a case of more rapid intoxication on the part of F. oxysporum. 



The results obtained with artificial media were verified by 

 infection experiments conducted with potato tubers kept at various 

 temperatures. Tubers of the Red Cobbler variety were used. 

 These were inoculated on April 1. and examined on May 27 

 < tabic [V I. Sec figs. 11 and 12. 



