134 



THE CANADIAN HORTICULTURIST. 



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Fig. 1771. Trametes radiciperda, (Root-Rot of Conifers), a, part of a fungus showing the crust fol- 

 lowing the irregularities of the bark, and the two projecting shelves d, both composed of several 

 overlapping shelves ; b, a section of the crust showing the three layers or thickness of tubes 

 I, 2, 3 ; (T, a portion of the spore-tube layer showing the tubes and their openings or pores 

 slightly magnified. (After Massee). 



are penetrated by the threads, which make 

 their way between the bark and the woody 

 part. Gradually the whole mass of tissue 

 of the cortex of the root, as high as the 

 crown, is literally choked with the fine 

 threads, and the vital activities of the plant 

 are seriously interfered with. During- late 

 stages of the disease I have frequently seen 

 the surface of the almost dead roots covered 

 with a matted, white felt of threads. 



The fungus is not content to remain on a 

 single tree, but will send out dark, radiating- 

 threads throug-h the soil to the roots of other 

 trees, which are attacked in a manner similar 

 to the first. 



Remedies. — From what has been already 

 said it is evident that there are tw^o sources 

 of infection of trees : (a) by spores, and (b) 

 by the fine black radiating strands under- 

 ground. These two sources sug-gest two 

 methods of treatment : (a) by preventing^ the 

 formation of the spores on the gills of the 

 cap, and (b) by isolating- infested trees, for 

 it is impossible to kill the fungus after it has 

 once made an entrance into the roots. All 



the fruiting- forms, or caps, should be de- 

 stroyed by burning. Infested trees, which 

 are considered too valuable and healthy to 

 destroy, should be isolated by a ditch about 

 ten inches deep, dug- around the tree. This 

 will prevent the underground strands from 

 reaching other trees. 



The disturbances produced by the pres- 

 ence of fungal threads are far-reaching-. 

 The transpiration of water, when the leaves 

 are affected, is seriously interfered with ; 

 the cells of the parts affected are gradually 

 destroyed throug-h the consumption of the 

 cell-contents ; and chemical chang-es are in- 

 itiated which results frequently in the mal- 

 formation, hypertrophy of tissues ; and 

 finally death ensues. 



(b) Root-Rot of Conifers. Trametes radi- 

 ciperda.^ (Fig^- ^11^-) This is a very common 

 fung-us on roots of conifers. The mycelium 

 may pass from a diseased root to another 

 close by which is not diseased, and in this 

 way a sing-le tree may infect a large number. 

 On infection, the cells of the wood become 

 browai, and white patches make their ap- 



