136 THE PEACH AND NECTARINE. 



The following season, numerous small wiry shoots 

 often grow from the larger branches, the leaves be- 

 come yellow, the whole tree assumes a sickly ap- 

 pearance, and eventually perishes. This disease 

 is still more to be dreaded from its contagious na- 

 ture. If not checked, it commonly spreads through 

 the whole orchard. It appears to be communicated 

 at the time of blossoming by means of the pollen. 

 But the infection may be conveyed in ether ways. 

 The bud from a diseased tree inserted in a healthy 

 stock, will cause its death, and even the use of a 

 knife in pruning, which has been previously used 

 on a diseased tree. Facts also greatly strengthen 

 the suspicion that the roots of healthy trees have 

 imbibed the contagion by mere contact with those 

 of diseased ones. It is also probable that planting 

 the seed of diseased trees will communicate the 

 disease to the seedlings. 



After it has once attacked a tree, there is no re- 

 medy; and to prevent it from spreading to others, 

 the diseased tree should be immediately destroyed. 

 No young trees should be planted on the same spot, 

 as the diseased roots still remain in the soil. Coxe 

 says, " The peach tree cannot be cultivated with 

 success on the site of a former plantation, until 

 some years of an intermediate course of cultivation 

 have intervened." As it is probable that the kerr 

 nel may become infected, caution would direct that 

 stones from diseased trees be never used for plant- 

 ing. 



