30 THE CONNECTICUT POMOLOGICAL SOCIETY. 



or variegation of plants, and certain diseases such as the 

 Yellows and the Rosette of the peach, the so-called 

 *' Calico" of Tobacco, and possibly others of a similar 

 nature. 



Whatever the cause of the Yellows, it is certain that as 

 yet we know of no remedy except that of rooting- out and 

 burning the diseased trees the moment the first symptoms 

 appear. This has been practiced so very thoroughly in 

 Michigan that the disease has been practically stamped out 

 in the State. 



After the Yellows, the most serious disease of the 

 peach is that known as crown gall. A tree affected Vv^ith 

 this disease presents at first a starved appearance, and pres- 

 ently, without apparent cause, it begins to die back. 



If you dig about such a tree you will find, just at the 

 crown of the roots, one or more wart-like growths varying 

 from the size of a walnut up to that of a potato, with a 

 rough exterior, but soft, like a potato. After a while these 

 warts begin to dry and become as hard as wood, and finally 

 they drop off and new ones are formed in their places. 

 You can cut these v/arts off, but they will come again. A 

 tree affected with this disease seldom lives more than two 

 years. Sometimes you find these knots on the trunks of 

 the tree, but in such cases you will always find them at the 

 crown of the root as well, and, when they are once found, 

 that tree is doomed. I have experimented with this dis- 

 ease by cutting off the knot from the crown of the roots 

 and dipping the latter in a solution of copper sulphate, but 

 without effect. From various experiments it has been 

 proved that Crown Gall is contagious over short distances 

 and if new trees are set in place of affected trees, they will 

 soon become diseased. It is also contagious between the 

 raspberry and the peach, and between the apple and the 

 peach, so that we have three classes of the disease ; on the 

 raspberry, on the peach and on the apple, all of which are 

 mutually contagious over short distances. 



In one instance, where a small nursery row of apples 

 had been affected with the Crown Gall, the trees were 

 removed, the land thoroughly cultivated and peaches set 

 in the row. These almost immediately became affected 



