280 BIOLOGY OF SPECIALIZED GROUPS 



Often specific systems in a plant are affected, and these 

 alone. For example, the vascular system may be occluded 

 (Fig. 54). At other times the bacteria invade the intra- 

 cellular spaces and form cavities (Fig. 55). At other times 

 there is a compensatory hyperplasia of cells and, as a result, 

 tumors are formed (Fig. 56). 



The following partial list gives a few of the bacterial dis- 

 eases produced in plants and some of the bacteria which 

 produce them. The bacteria are in some instances not 

 specific and certain species of bacteria may cause disease 

 in several species of plants. 



Tobacco wilt Pseudomonas solancearum 



Cucumber wilt Bacillus ariodeae 



Melon wilt Bacillus tracheiphilus 



Tomato wilt Pseudomonas solancearum 



Blight or spots on green apples, quinces, 



prunes, pears, plums, etc Bacillus amylovorus 



Potato rot Pseudomonas solancearum 



Turnip rot Pseudomonas campestre 



Carrot rot , Bacillus carotovorus 



Diseases of the leaves and stems of cot- 

 ton, sweet corn, broom corn, cabbage, 



etc. 



Pseudomonas vascularum 

 Pseudomonas campestre 

 Pseudomonas malvacearum 

 Bacterial olive knots (tumors) .... Pseudomonas steward 

 Disease of walnuts, flowers of plants, f Pseudomonas hyacinthi 

 etc 1 Pseudomonas jugulandes 



