DISEASES OF THE APPLE. 247 



with the disease realize that this is next to the impossible. If 

 the cedar trees are valued, as they undoubtedly are, they may 

 be saved and the disease on the apple at least checked by the 

 use of the Bordeaux spray, as shov^rn by Professor Emerson. 



"Two sprayings with Bordeaux mixture, the first at the time 

 the apples on the cedar trees were becoming orange colored and 

 gelatinous, and the second two weeks later, kept the apple 

 foliage practically free from rust. The average number of rust 

 spots per hundred leaves from sprayed and unsprayed apple 

 trees were as follows : 



Sprayed, Wealthy 19; Jonathan, 13. 



Unsprayed, Wealthy 260; Jonathan 112. 



Unless the disease is perennial on the red cedar it can prob- 

 ably be stamped out by spraying. 



RHIZOMORPHIC ROOT-ROT. 



Cause: The disease is caused by a parasitic fungus {GUtocyhe 

 parasitica.) 



Description: The fungus enters the tree near the surface of 

 the ground, works its way through the roots, and by delicate 

 white threads {mycelium) penetrates the ground and infects root 

 after root. These fungi ordinarily work on decaying wood or 

 other vegetable matter, but readily adapt themselves to living 

 plants, if they have a chance to enter through some wound, such 

 as a cut root. The disease is first noticed by the turning yeUow 

 of the leaves, caused by a decreased food supply. Next the 

 bark withers and the fruit becomes wrinkled and drops. 



Hoio spread: It is claimed by the Oklahoma station that the 

 mycelia make their way through the ground ten or fifteen feet. 

 The disease is spread by the spores which are borne on the 

 fruits. These fruits appear on the trunks of the trees. The 

 spores are carried by wind and by insects. 



Treatment: There is little that can be done to check the rav- 

 ages of the disease on the tree if it once gets started. A 

 diseased tree should be destroyed as soon as it is past its 

 usefulness. It has been recommended that a ditch about two 

 feet deep be dug around the tree to prevent the spread of the 

 disease by the mycelium. The wounds on the roots should be 



