Diseases of the Sugar Beet, 



349 



The leaves were usuall}^ unaffected until large portions of the 

 fleshy roots had rotted. Cultures from diseased parts again 

 yielded a fungus with structural characters exactly similar to 

 those of the sore shin and damping off fungus. 



When the beet fungus was first isolated and studied I was sur- 

 prised to find a fungus agreeing in structural details with the 

 one causing damping off, radish rot, &c. The growth characters 

 of the fungi in pure culture were also practically the same, 

 and experi- 

 ments were 

 soon insti- 

 tuted to de- 

 termine if, 

 under any 

 c i r c u m- 

 stances,the 

 beet f u n - 

 gus could 

 cause 

 damp in g- 

 off. In the 

 first exper- 

 iments t o 

 deter m i ne 

 this point, . 

 lettuce and 



radish seedlings were used. Small pieces of beet on which the 

 beet fungus was growing profusely were put at definitely marked 

 places in a large box of lettuce seedlings on Sept. 26. Similar 

 inoculations were made in a box of radish seedlings, and in both 

 instances checks were observed. On the second day, at every 

 point where the the beet Rhizodonia had been introduced a few 

 lettuce seedlings were diseased, and in five days a considerable 

 area about each piece had damped off. With the radish seedlings 

 damping off was very slow, and no large number of seedlings 

 succumbed ; but in seven days a few plants were affected at about 

 one-half of the inoculation centers. Subsequent work seems to 

 indicate that the fungus from beets does not cause damping off of 



55. — Radishes affected with soft rot of the crown. 



