DISEASES. 2 3 I 



The mealy or white American bug, Coccus laricis, is 

 an insect commonly found on unhealthy larches at the 

 various stages of growth, chiefly in sheltered situations 

 and upon damp soils, in excessive wet, cold, or dry 

 seasons, after frost or scorching suns. I do not consi- 

 der the effects of this insect fatal to the tree generally, 

 as it neither eats the leaves nor breaks the rind, but 

 its presence is always an indication of an unhealthy 

 state, and by remaining long upon the tree may aggra- 

 vate or even lay the foundation of permanent disease. 

 Trees in their younger stages of growth are much more 

 liable to attacks of the Coccus laricis than advanced 

 and old trees, and this goes far to establish the opinion 

 that free exposure is essential to the healthy growth of 

 the tree. 



That much good can be done to sickly or diseased 

 larch plantations under certain conditions, I am quite 

 certain of ; for example, thinning, or cutting down 

 undergrowth or rank herbage which is preventing the 

 air from circulating through the plantation, paring off 

 the matted grassy turf, or turning it upside down, and 

 draining so as to carry off stagnant water, &c. 



Cold hard winds and excessive sea exposure do not 

 suit the larch, hence the margins of plantations specially 

 so exposed should be bordered with a row of sycamore, 

 mountain ash, or silver fir. 



The larch may well be regarded as both a very 

 tender and yet a very hardy forest tree. It is exceed- 

 ingly tender and sensitive of frost when in leaf, and 

 even before the leaf breaks, and when perhaps 6° of 



