146 Journal of Agricultural Research voi. iv. no. 2 



still others through wounds on the petiole or in the heart of the crown. 

 In no case was there any evidence of rot in the field or at the time of 

 harvest. It was at first believed that climatic conditions were respon- 

 sible for the failure. However, the beets were placed in storage. The 

 following spring they were examined for evidences of Phoma betae by 

 culture methods. None of the beets had been destroyed; indeed, most 

 of them appeared to be perfectly sound until they were opened, when the 

 black lines previously mentioned appeared in the vascular regions. 

 Cultures were obtained from each of the infected beets, except two. These 

 results were at first interpreted as an indication that the inoculations 

 made in August had produced infection which had persisted on the sur- 

 face and penetrated the roots in storage, but subsequent developments 

 throw doubt upon this conclusion and indicate that the infection oc- 

 curred much earlier. About half a ton of beets grown as controls had 

 been placed in storage beside the infected material, but in a lower rack. 

 Evidences of rot were observed in only half a dozen of these beets, and 

 they yielded cultures of Phoma betae. It was noted at the time of 

 examination that the control beets, which had been kept nearer the 

 surface of the soil, were all firmer than the inoculated material; but 

 unfortunately no significance was attached to this fact at the time, and, 

 with the exception of 12 of the control beets, the entire lot of material 

 was sent to the feeding sheds. 



A few weeks later a large quantity of mother beets grown in the vicinity 

 of the experimental field from western seed was found to be seriously in- 

 jured by the Phoma rot, practically every beet showing more or less evi- 

 dence of it. These beets had been bored for analysis in the fall, so that 

 any evidence of infection at that time would have been apparent. The 

 decay did not originate from infection in the wound made by boring, as 

 may be seen readily by reference to the illustration (PI. XIX). In the 

 large majority of cases the rot evidently started from the crown, although 

 there were cases of pockets of decay on the sides or even at the tip of the 

 beet. In some instances dark streaks could be traced from the crown to 

 decayed areas in the lower portion. This led to the belief that the decay 

 in beets inoculated with Phoma betae was due to infection occurring in 

 the seedling stage and that its development was fostered by the less 

 favorable, dryer conditions of storage to which they were submitted. 

 Additional evidence for this belief is to be found in the results of the 

 inoculation experiments with Rhizoctonia (p. 153), since the Phoma 

 rot appeared upon this material also. Moreover, of the few control beets 

 saved from the feeding sheds all but three developed Phoma decay during 

 the late spring and early summer, and cultures of PhoTna betae were 

 secured from darkened bundles in the crowns of these three. It might 

 be urged that the infection reached the crowns of these beets by way of 

 the petioles from Phyllosticta upon the leaves. This seems a very prob- 

 able means of infection, but appears unlikely in the instances above cited, 



