Diseases of the Cak.natiox. 



169 



old age or became so debilitated as to fall an easy prej^ 

 to some of the diseases about which we then knew so 

 little. I remember also that some years since, when 

 living where land was scarce, this trouble was more 

 frequent among plants grown for two or more years upon 

 the same ground. An experience of many years with 

 various species of plants, has convinced me that almost 

 without exception, health and vigor are best preserved 

 when a system of rotation is strictly adhered to. I do 

 not believe the carnation is an exception to the gen- 

 eral rule, but on the contrary, that disease is less liable 

 to attack plants full of vigor, and that this vigor is in- 

 creased when the plants are grown in fresh soil each 

 season. 



Fig. 34. 



Rust, a later and very dangerous enemy, scientists 

 tell us is a fungus, and spreads with great rapiditj'. It 

 is only within a few days that the writer has seen this 

 pest, and from what little was seen of it then, he be- 

 came convinced it was a disease every grower should 

 take the utmost precaution to avoid. There is no 

 doubt but that it is highly contagious, and if once seen, 

 vigorous measures should be taken to stamp it out. It 

 first appears on the leaves in form of small brown 



