132 THE CHRYSANTHEMUM 



indicates that it is less vigorous in its attacks. In 

 general, when a rust is confined to the uredo forms 

 for a number of generations, its vitality is much reduced 

 and also its power of injuring the crops/' 



This probably explains the reason why growers 

 have been able to gain the upper hand, as by prompt 

 attack and by timely removal of diseased parts, they 

 have, in large degree, prevented the reaching of the 

 teleutospore stage. From the foregoing will be appar- 

 ent to those who grow Chrysanthemums in the open air 

 the desirability of not again planting Chrysanthemums 

 upon the same spot for two- or three years if they have 

 been attacked with rust, since the teleutospores are 

 almost sure to be present in the ground. 



Leaf Spot is the name commonly given to another 

 disease undoubtedly of a fungous character, and one 

 hard to combat when it makes its appearance. Pre- 

 vention, however, is easily possible, as it is a condition 

 of ill health arising almost wholly from causes over 

 which the grower has control. Its appearance is de- 

 noted by small spots or patches of a brownish or black 

 color which quickly spread, and are so rapidly conta- 

 gious that a continuance of conditions congenial to its 

 growth will soon result in its spreading furiously till 

 the plants are completely denuded of leaves. They 

 quickly die and dry up when once infected. This dis- 

 ease is engendered by overcrowding and consequent 

 inability of the air to circulate freely among the 

 plants. Spraying with sulphide of potassium or with 

 Bordeaux mixture may be resorted to, but these reme- 

 dies are only slightly deterrent; the only effectual way 

 is to correct the conditions that give rise* to the attack. 

 For example, leaf spot used to cause some trouble 

 in some benches of Chrysanthemums that were six feet 

 in width, and the initial attack always began upon the 



