THE BROWN ROT OF SOLANACEAE : TYPE 



181 



paeolum and Impatiens also have a livid color (see Fig. 1265) 

 and ooze bacteria through rifts and stomata or on cross-section 

 (Figs. 130 and 2125). 



It is commonly a wound-infection disease, but infection may 

 also occur through stomata. More often than not the bacteria 

 enter the plant underground, through broken or punctured roots. 

 It is easy to obtain the disease experimentally on Datura, Tro- 



FIG. 124. Young tobacco plant inoculated with Bacterium solanacearum by 

 needle-pricks and photographed at the end of 17 days. The bundles of stem and 

 leaves were browned and swarming with the bacteria. The plant showed marked 

 dwarfing before it wilted. Inoculated May 1, 1915, with "Creedmore" of lessened 

 virulence. Plated in 1914 from North Carolina tobacco. Photographed May 17. 

 Check plant at left. 



paeolum, and Ricinus by means of broken roots. The disease 

 is very apt to occur in carelessly transplanted seedlings or in 

 plants whose root-system is attacked by parasitic nematodes 

 (Heterodera radicicola), or is gnawed by insects. 



It is a disease in which there is often a conspicuous dwarfing 

 of attacked parts (Figs. 121 X, 127 and 131). Young soft tissues 

 are more subject to the disease than those containing less water. 



