PESTS. 57 



give beneficial results. A closely allied species, C. comedens, 

 Fries, is parasitic on young oak branches. 



Root Diseases. Fomes semitostus, Berk., has been found 

 attacking Hevea roots both in Ceylon and the Straits Settle- 

 ments. Fetch states : * " Fames semitostus always develops first 

 on jungle stumps, and spreads from them to the Hevea by 

 means of white threads in the soil. There is no case in Ceylon 

 of a direct attack on Hevea, and the fructification has never been 

 found on Hevea in Ceylon, except in the case of those cultivated 

 for the purpose at Peradeniya. The spores of the fungus are 

 blown on to the jungle stump and develop there until the stump 

 is partly consumed. The mycelium then spreads to the neigh- 

 bouring trees, and at the same time advertises its presence by 

 producing its fructification on the stump. I have never found 

 any difficulty in deciding which stump the fungus originated on. 

 The method of prevention is obvious, though it may be expen- 

 sive. Jungle stumps must be removed." 



" The fruiting portion of Fomes semitostus is a broad, flat, 

 rounded plate often very irregular in form, usually reniform, 4 to 

 6 inches across, and of an orange-red colour beneath, paler above, 

 where it is marked with rings and fine striae ; beneath can be 

 seen with a lens the honeycomb-like structure of the hymeneal 

 surface. The texture of the fungus is tough, and it possesses a 

 strong mushroom-like scent" f 



Several species of fungi belonging to this genus cause various 

 tree diseases, the best known being " Root-rot of Conifers," 

 " Tinder Fungus," and " Gooseberry Polyporus." In addition to 

 destroying all tree stumps in the neighbourhood, and infected 

 Heveas, the ground in which the latter were growing should be 

 isolated by encircling it with a narrow trench to prevent the 

 mycelium spreading. 



In the Straits Settlements, a fungus (Helicobasidium sp.) has 

 been found attacking the roots of the tree. A species of the 

 same genus is reported by Massee to be very destructive to 

 mulberry trees in Japan. This fungus rapidly spreads from tree 

 to tree by the agency of strands of mycelium in the soil. Should 



* " Lectures and Discussions on Rubber Cultivation and Preparation, 

 Ferguson, 1906. 



t Ag. Bull, of the St. Settlements and F.M. States, May 1904. 



