The Enemies of Trees 



wood are also among the well-known fungous growths that 

 disfigure trees. The shelf fungi are the largest. Many kinds of 

 destroying fungi may attack a single tree. Every enfeebled tree 

 is increasingly vulnerable. Dead trees are gradually devoured 

 by fungous organisms. 



Protection against fungous diseases is not practicable yet 

 in the forests. In orchards and home grounds and parks spraying 

 is used as a preventive. Compounds of copper destroy the spores 

 of fungi. It is asserted that one part of copper sulphate in ten 

 thousand parts of water will prevent the germination of a spore 

 of apple scab or pear-leaf blight. Lime water is added to keep the 

 copper sulphate from burning the foliage. Copper, lime, and a large 

 proportion of water make the so-called "Bordeaux mixture" — 

 the standard fungicide in the orchards and vineyards of Europe and 

 America. Two or three sprayings a year, the first just before the 

 leaves open, will keep a healthy forest tree free from fungous 

 troubles, while neighbour trees and their fruit are badly damaged 

 by rot and other fungous attacks. 



Bacterial diseases that enter the growing shoots of trees and 

 develop within them are well illustrated by the "fire blight" of 

 the pear. No fungicide can reach and check this disorder. The 

 affected parts should be cut off and burned. Often burning the 

 whole tree is the only safe method, as otherwise contagion will 

 spread to other trees. 



Constitutional diseases are found among trees, as well as in 

 the human family, and no explanation of their causes nor hint 

 of proper treatment has been discovered. "Peach yellows" 

 is an example. It is the moral, if not the legal, obligation of every 

 owner of a tree thus afflicted to dig it out and burn it, root and 

 branch, in order that the disease may be kept from spreading. 

 Tree diseases are not all disseminated by the wind. Some live 

 underground, carrying infection by contact of root tips from 

 unsound to sound trees. 



Insects form a large body of the enemies of trees, inflicting 

 untold damage each year upon orchards and forests, and upon 

 trees everywhere. Each species has its insect enemies, not one, 

 but more — often many. There are borers that infest the solid 

 wood, channelling it and ruining it for timber, or working just 

 under the bark, sapping the cambium, which is the tree's life. 

 Some borers work in the twigs, causing the young shoots to die 



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