224 LARCH. 



tions ; it suffers from drought and from exposure of its roots 

 to sunshine, and also from a stagnant wet soil. Although it 

 requires a constant supply of moisture for its roots, this 

 moisture must be fresh, and free ; and it needs a clear, dry 

 atmosphere, with great amount of sunshine for its leaves. 



A position amongst broken rock, with plenty of good loam, 

 either on the side of a ravine or so placed that water may 

 constantly trickle by, may be considered the type of what is 

 most suitable for its growth ; in its natural habitats it thrives 

 best on declivities connected with summits of perpetual snow, 

 by the thawing of which the plants are fed, and where their 

 heads are well exposed to sunlight. 



It has been pointed out by Prof. DeCandolle that the fine 

 slender Larch leaves having less surface for action (that is, 

 for elaboration of sap) than those of other deciduous trees, 

 the action of the surface requires to be greater in proportion, 

 to keep the tree in health ; and from this, and also from 

 observation of the localities in which Larch thrives, he shows 

 the desirableness of a clear dry atmosphere, with plenty of 

 sunlight, and freedom from fogs and damp, which tend to 

 diminish the evaporation from the leaves necessary for the 

 health of the tree ; and — to give a single instance — it is noted 

 that at a height near Geneva (not less than that at which fine 

 Larches were to be found) the trees did not thrive near the 

 lake and river, whilst in the dry air of the Alps they prospered. 



It appears plain that any cause, great or small, that induces 

 a damp stagnant atmosphere, or want of light round the 

 Larches, will produce ill-health, and in such situations the 

 Larch Bug thrives. 



We may do something to diminish the amount of attack by 

 planting on proper soil, and especially avoiding such flat 

 moorish land as is likely to cause stagnation of moisture in 

 the ground ; and also by thinning Larch plantations in time, 

 so as to allow as much sunshine as possible on the leaves ; 

 and all overtopping by deciduous trees should be carefully 

 avoided. 



Hopelessly attacked trees should be felled and all the twigs 

 burnt, to avoid spread of attack ; and in nurseries it might be 

 worth while, besides the dressings given when the Bug is seen 

 to be present, to give one or two thorough drenchings with 

 soft-soap towards the middle or end of August, to deter attack 

 when the eggs for next year's " mother (Dhermes " are being 

 laid. 



With regard to such connection as may exist between 

 " Larch Blight " and the diseased cancerous formations known 

 as "Larch Blister," we have no certain knowledge at present. 



The causes mainly under consideration as giving rise to this 



