DISEASES OF FOREST TREES. 289 



CHAPTER 11. 



DISEASES OF FOREST TREES. 



Euonymus Mildew (Qidium euonymi-jai3onic«?).— 

 The euonymus is occasionally attacked by a fungus which 

 develops in white patches on the leaves and shoots. In 

 a few cases we have seen the whole plant attacked. If 

 allowed to increase, it seriously cripples the growth of the 

 plant. 



Kemedies. — (1) Collect all diseased shoots and leaves 

 and burn them. (2) Dust the bushes, when damp, with 

 flowers of sulphur. (3) Spray with Sulphide of Potassium 

 Solution. 



Larch Canker Disease (Dascypha calycina).— 

 Many plantations of larch have been badly injured by 

 this fungus. It appears to attack trees growing in damp 

 situations and where they are much crowded together. 

 The disease gains access to the trees through the medium 

 of punctures or wounds. The mycelium develops under 

 the bark, causes a resinous exudation to form, and the 

 ultimate death of the bark in the region of infection. 



Remedies. — Where badly attacked the best plan is to 

 cut down and burn the trees. Where only slightly 

 attacked, pare away all the diseased parts, then wash 

 with a solution of sulphate of iron and paint with Stock- 

 holm tar. 



Sycamore Leaf Blotch (Rhytisma acerinum). — 

 The leaves of the sycamore and maple are often disfigured 

 in late summer by black blotches. These first appear of 

 a yellow tint, and then turn quite black. The presence 

 of this fungus on the leaves seriously interferes with their 



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