"WITCH'S BROOM" ON JAPANESE CHERRIES 



347 



mony to the destructive power of thechcstnut blight and the 

 white pine blister, both diseases imported from abroad on 

 nursery stock from which they spread to our native species. 

 In Hke fashion many other diseases of trees and shrubs, 

 as well as dangerous insects and diseases of animals and 

 human beings, have been transplanted from one part of the 

 world to another with enormous losses resulting from their 

 unbridled, destructive activities. ' ' An ounce of prevention 

 is worth a pound of cure," and it is with that idea in mind, 

 rather than any definite knowledge of grave danger, that 



try wherever the climate is favorable to their growth and 

 development. This wide distribution gives the problem a 

 serious aspect, for the eradication of the disease is thus 

 made very difficult. 



Following the discovery of the disease on the Japanese 

 trees in the District of Columbia, specimens of European 

 cherry in other places were also found to be affected simi- 

 larly, but whether the disease is the same has not been 

 determined. Although the life history of the disease has 

 not been worked out, some general information regarding 

 it is available. Investigation has shown that the infection 



EFFEl r (IF ■■ Win ITS likl » i.M ' 



JAI'.W I', 



' 1< 'V 



This is another of the trees presented to President Taft by the Japanese Govern- 

 ment. In this case the right-hand branch is free from infection, while the left 

 one has several brooms on it. After a branch is attacked it will continue to grow, 

 but will rarely, if ever, develop either flowers or fruit. 



a warning is issued against imported ornamental cherry 

 trees which may be infected by the recently discovered or 

 a similar disease. 



The flowering cherry trees of Japan have attained world- 

 wide fame because of their beauty and decorative value 

 and have naturally been imported into this country in con- 

 siderable numbers for ornamental purposes. Owners of 

 many large estates have purchased them for this purpose 

 and they can be found here and there throughout the coun- 



INFECTED LEAVES OF JAPANESE CHERRY 



This close-up view of an infected tree shows how the spore-bearing bodies on the 

 under side of the leaves cause them to crinkle. These spores ripen just after the 

 blossoms are out and are blown from one tree to another when the leaves are 

 small and tender. Normal leaves can be seen among the crinkled ones, and this 

 comparison is the best way to ascertain whether or not leaves are infected, as the 

 spore-bearing bodies are apparent only as a faint white bloom almost invisible to 

 any but the practiced eye. 



is caused by a parasitic fungus — one that lives on the tree, 

 drawing its nourishment from the living tissues but at the 

 same time allowing the tree to live. The life activity of the 

 tree is so changed by the parasite, however, that while pro- 

 ducing for a time an extra dense foHage growth, it does not 

 produce flowers or fruit, as all the flower buds become leaf 

 buds. The dense aborted growth is the result of the tree's 

 response to the stimulus of the attacking disease. 



The illustrations show the characteristic appearance of 

 infected trees. In the first a normal tree is shown at the 

 right in order to bring out the contrast with the diseased 

 specimen. The diseased tree shown was evidently infected 



