i6 



Research Bulletin No. g 



the major part of the potato troubles to the activity of this organism. 

 Even though it is not the sole or even the main cause of Nebraska 

 potato troubles it may play an important role. The work of 

 Appel (2), Corsault (8), Drayton (9), and Morse and Schap- 

 ovalov (26) gave results similar to those obtained by Rolfs 

 (31.32). 



Fig. 2. — Wilt produced in laboratory with Fusarium trichothecioides, and control 

 plant; A, control, Early Ohio variety; B, wilting and drying of leaves, 4 days after 

 inoculation, Early Ohio variety. 



On March 13, 24 plants grown in sterile soil were used in another 

 experiment. These plants were about 10 cm. high at the time. 

 The soil was removed from one shoot in each pot and the pots were 

 arranged in 6 series. In series A the shoots were wounded and the 

 wound smeared with F. oxysporum infected rice; in series B the 

 sound stem was smeared with F. oxysporum infected rice; in series 

 C the wounded shoots were smeared with F. trichothecioides infected 

 rice; in series D the sound stems were smeared with F. tri- 

 chothecioides infected rice; in series E no inoculum was applied to 

 the wounded shoots; in series F the soil was merely removed and 

 replaced (figs. 2 and 3). 



