CEDAR RUST ON THE APPLE 209 



Liquid asphaltum has as a rule given better results than the 

 solid. This is probably due to the fact that a better job of covering 

 may be done. No ill effects have been noted from the use of any of the 

 preparations of liquid asphaltum. 



The key to success in treating canker is thorough and careful 

 •work. In pruning all cuts should be made smooth and close, and 

 Fhould be covered immediately. All dead and diseased limbs should be 

 removed. Pruning tools should be disinfected after every tree and 

 after cutting into any canker part of a tree. All dead trees and all 

 pruned wood should be removed from the orchard at once and burned. 

 No cankered spot should be left uncovered on any tree, for just as long 

 as such spots are uncovered just so long will there be canker spores 

 to jinfect the remaining trees. When spraying every part of the 

 tree should be sprayed thoroughly. When these measures of sanita- 

 tion are carried out, and not until then, will we be able to control the 

 Illinois canker. 



CEDAR KIST ON THE APPLE. 

 J. R. Cooper. 



Cedar rust of apples (gymnosporangium macropus) is one of the 

 most widespread and economically important diseases of the apple. 

 It is found all over the eastern and central portions of the United 

 Slates. The disease is not found except in regions where both red 

 cedars and apples grow. The abundance of red cedars in Nebraska 

 and the large number of susceptible varieties of apples in the state is 

 the principle reason why this disease is so abundant. Orchards in 

 the vicinity of the cedar trees always suffer more severely than 

 those farther away. 



Other diseases and insects are often blamed for the damages 

 caused by cedar rust. If proper credit were given this disease for 

 all the loss it causes it would amount to many thousands of dollars 

 annually, regardless of the loss due to weakening of the trees and 

 to impairing the vitality of the fruit buds. 



The foliage is the first to suffer, and usually it is the foliage 

 which suffers most, though the twigs and fruit are also attacked. 

 Early in the growing season the leaves begin to show bright orange 

 colored spots. Upon these spots soon appear small pimple like pro- 

 tuberances (pustules) on the upper surface. These pustules, at first 

 yellow, soon turn black and exude a sweet viscid substance. The 

 orange colored spots become larger and more thickened as the sea- 

 son advances. After the first of July small tubular openings appear 

 on the lower surfaces from which spores are exuded. In cases of 

 severe infection almost the entire surface of the leaves are covered 

 with rust spots, and in some cases the trees are entirely defoliated 

 by the last of August. Many trees succumb entirely, especially if the 

 season is dry, while on those which survive the fruit is often so 

 small as to be unsalable. 



