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ENCYCLOPEDIA OF PRACTICAL HORTICULTURE 



Fig. 1. Rust on Apple Foliase and Cedar Ap- 

 ple.' (New Hampshire Experiment Station.) 



effects produced is the so-called "cedar 

 apples." The fungus passes the winter on 

 the Juniper and in the spring produces 

 gelatinous outgrowths that contain numer- 

 ous spores. These spores, when borne 

 hack to the apple foliage, produce the rust 

 again, and thus the fungus passes from 

 one host back to the other. 



Treatment 



Spraying has not usually been very 

 effective in controlling the disease. Since 

 the Junipers harbor the fungus through 

 the winter the method of control is, obvi- 

 ously, to destroy them. 



Charles Brooks 



The Pacific Coast Cedar Rust of the 



Apple, Pear, Quince and Related 



Pome Fruits 



Oymnosporangium hlasdaleanum 

 For several years the writer has been 

 studying a rust on several cultivated and 

 native species of the pome family. In 

 1908 the fruiting stage of this rust was 

 found on the serviceberry, and on the 

 thorn apple or haw. Later the same spe- 

 cies was found on the apple, pear, quince 



and the native pome fruits as noted be- 

 low. 



The final stage of this rust is found on 

 the incense cedar. 



During the past six years the writer 

 has paid particular attention to this rust, 

 for the reason that it is of considerable 

 economic importance. While it occurs 

 rather sparingly on all varieties of apples 

 so far observed, it has been found to at- 

 tack certain varieties of pears very seri- 

 ously. The quince is also subject to con- 

 siderable injury by this rust. 



In 1910 and again in 1912 serious in- 

 fections of this rust were noted in some 

 orchards in the Rogue River valley. In 

 1912 the writer's attention was called to 

 a very serious infection in a small block 

 of pears of the Winter Nelis variety 

 which practically destroyed 95 per cent of 

 the crop. The fruit was badly deformed 

 and fully 50 per cent of the leaves were 

 found infected. The attention of the 

 writer was called to this orchard by P. E. 

 Zepp, who brought specimens to the labo- 

 ratory and who, under date of June 20, 

 1912, wrote the following in answer to an 

 inquiry made by the writer: 



"A block of 150 pear trees (mostly Win- 

 ter Nelis) on the west side of the orchard 

 was so badly diseased that the entire 

 crop was lost. The fruits were covered 

 with yellow spots and were all twisted 

 out of shape. Later, these fruits dropped 

 off. The foliage was also badly injured 

 and it was hard to find a leaf that was 

 not attacked. There were other varieties 

 in the orchard that also had rust on them. 

 Even Kieffer pears were attacked, but the 

 Winter Nelis was most hurt." 



All varieties of pears are not equally 

 susceptible, but both European and Ori- 

 ental varieties were found affected. Ori- 

 ental hybrids, such as the Kieffer, showed 

 infection in a more or less serious degree. 

 The incense cedar, which bears the resting 

 stage, is very common in Southern Ore- 

 gon, being found on the floor of the Rogue 

 River valley and on the dry hillsides. The 

 rust was not noted as affecting the cul- 

 tivated pome fruits until the orchards 

 were pushed into the foothills in the 



