PLATE 24. 





2?r 





Brown rot of the potato. 



Potato-tuber from Hastings. Florida, crop of 1 905, sound externally, but brown-rotted in the vascular system, the bacteria having entered 

 through the vessels of the underground stem. Bacterium solanacearum was plated out and subcultures were used to infect potted potato- 

 plants. The plant shown was inoculated on June 27. by delicate needle-pricks. Disease more advanced on one incKulated =hoot than on 

 the other: later this also shriveled. Tuber natural size; photographed May 29, Plant about one-fifth natural size; photographed 

 July 15, 1905. 



