SPOT, OR SPOT DISEASE. l6l 



the injuries they produce maybe given as follows: 

 (i) spot, or spot disease; (2) wilt, or stem rot; (3) 

 nanism, or stuntedness; (4) scald, or edge burn; 

 (5) oedema, or wart disease; (6) crown rot, and 

 (7) root galls, or nematodes. 



Spot, or Spot Disease* This is generally re- 

 ferred to as "the violet disease," and is recog- 

 nized by growers generally as the most serious 

 enemy with which they have to deal. Much has 

 been written about it and many theories have 

 been advanced as to its cause. There is no 

 question that spot can be produced in many ways, 

 and may result from the attacks of a number 

 of different fungi. The true spot disease, how- 

 ever (the one which under certain conditions may 

 sweep away an entire field or house of plants in a 

 few weeks), has always associated with it a specific 

 fungus. The fungus is found wherever there is 

 true spot and the spot occurs in this country wher- 

 ever the violet is grown. There can be no doubt 

 as to the relation of this fungus to the disease, for 

 time and time again the connection has been 

 proved by careful scientific experiments. The 

 fungus itself is an undescribed species of Alter- 

 naria, and can be grown, watched, and handled as 

 readily as the violet plant upon which it lives. The 

 writer has never seen a house, a frame, or a field 

 where this fungus was not present, and plants 

 have been examined from Massachusetts to Cali- 

 fornia. Often spotted leaves are found on which 



