166 [ DISEASES OF THE MULBERRY 



of a viscid dirty brown liquid which soils the wound 

 and the bark of the stem below it. The bottom of 

 the wound whether consisting of the inner bark or of 

 the wood, becomes yellowish brown and of stony hardness. 

 When this diseased condition becomes fully established, 

 the wound hardly ever heals, the cambium being too 

 much exhausted by the continuous exudation to form 

 the usual covering of new tissue over the wound, and 

 after a variable period the wound gives place to canker 

 which destroys the heartwood for a considerable length 

 of the trunk, and ultimately kills the tree. As there 

 is little doubt that the disease is due to a microbe, 

 it is recommended to scrape well the wound until the 

 healthy bark and wood are reached, then to apply 

 repeatedly by means of a brush a strong solution of 

 sulphate of copper (5 per cent.) and when dry, to paint 

 the wound well over with tar. 



Polyporus hispidus (Bull) Sacc. is a fungus of woody 

 texture often met with on the mulberry, and also but 

 rarely on the walnut, its mycelium feeds on and 

 destroys the wood of the stem and branches and in 

 due time its characteristic pileus buds out of the bark, 

 sometimes reaching the size of a horse's hoof. Its colour 

 is dark chocolate brown, with short brown hairs. Polyporus 

 kirsutus Fr. is a rarer species sometimes attacking the 

 mulberry. Its pileum is much smaller than that of 

 P. hispidus. However, both species seem to be very 

 virulent, their spawn or mycelium spreading rapidly 

 through the wood for long distances along the trunk 

 and branches, reducing the wood to a black crumbling 

 mass, so that when the pileum makes its appearance 

 the disease has already spread beyond remedy. The 

 pilea should be cut off at once as soon as they appear, 

 and burned, in order to save the other trees from 

 infection. The diseased tree may have a lingering life 

 of several years, but ultimately dies, or is blown down 

 by the wind, all its wood being rotten and therefore 

 offering no resistance. 



