FOREST PROTECTION 91 



surfaces should be painted with an antiseptic substance, such 

 as coal-tar. 



LARCH CANKER, Peziza Will^ommn. In countries with a 

 moist climate, and especially in low-lying situations subject to 

 mist and frost, Larch is subject to this fungoid pest. The 

 tendency is aggravated when the species is grown in pure 

 woods, upon unsuitable soil, or in crowded plantations. 



Somewhat oval -shaped "blisters," exudation of resin 

 from fissures in the bark, and the small cup-shaped asco- 

 phores (with their whitish borders and orange -coloured 

 centres) are evidence of the pest. Both the stem and 

 branches become cankered and bear the fructifications. The 

 mycelium lives in the soft bast, kills the cambium, and can 

 pierce to the pith along the medullary rays. The canker or 

 blister extends by growth around its periphery ; when its 

 increase is more rapid than that of the tree-stem, the latter is 

 encircled and killed, or the flow of sap may be so impeded 

 that death results. In all cases affected stems are seriously 

 crippled by the disease. 



Amongst predisposing influences are the attacks of the 

 Larch Aphis (Chermes lands] and the Larch Mining Moth 

 (Coleophora laricella). 



Prevention : Careful selection of site. Avoidance of 

 pure woods. Thin mixture of Larch where possible 

 with Beech. Where conditions are at all unfavourable to 

 the growth of Larch, other species should be substituted 

 for it. 



NEEDLE-SHEDDING WGUS,Ifysterium (Lophodermium)pinastrL 

 Occurs to some extent upon Scots Pine of all ages, but it is 

 only two- to six-years-old plants that suffer severely. Upon 

 the latter it comes as a dreadful scourge in some localities, for 

 it destroys the assimilating organs of the plants. In autumn 

 discoloured spots or blotches may be seen, and later the 

 needles turn brown and fall off. With weak plants the 

 disease is apt to prove fatal. It especially haunts closely 

 sown nursery beds, and if these be .situated in the vicinity of 

 Pine woods the danger is intensified. 



