228 THE LARCH. 
remain free from the insect for many years. From the extent 
and nature of the field in which the insect prevails, no prac- 
ticable cure is likely to be discovered beyond that of using 
the best means to promote the health of the plantation. 
When the soil is congenial, and the plants acclimatized (that 
is, the produce of Scotch seed), there is little to fear from this 
insect. 
The larch is subject to an atmospheric blight, which is 
often observed to some extent, but it- sometimes falls with 
great severity. It occurs at various periods when the tree is 
in leaf, but most frequently about the end of July or the 
beginning of August. It blasts the foliage, giving it a 
yellowish tinge or ripened appearance, particularly the oldest 
leaves, those recently expanded appearing only slightly 
affected, except in severe cases. Its effects are frequently 
ascribed to frost, but it commonly occurs during warm wea- 
ther, when the thermometer indicates a high temperature. 
Throughout some districts it attracted little notice until its 
effects the following summer, by the want of foliage, exhibited 
numerous dead twigs throughout the tree. During the sum- 
mer of 1850, this blight severely injured the larch plantations 
throughout Scotland ; other trees also, in some districts, suf- 
fered, but in a less degree, from the same casualty. Ina 
plantation composed of larch and Scotch pine, twenty-four 
years old, situated in Inverness-shire, upwards of 1000 feet 
above the level of the sea, where the progress of some of the 
trees was marked yearly, the larches were tallest, but pre- 
viously to 1850 their girths, on an average, were equal. 
During that year, however, on account of this casualty, the 
marked larches barely made any perceptible increase, while 
the Scotch pine made an increase of nearly three inches, 
namely, from 27} to 30 inches in girth. 
The rot in larch is a disease which has been noticed by 
various writers on larch since the beginning of the present 
century. In some parts it is known by the term pumping, 
doubtless from the resemblance which the hollow trunk bears 
to a wooden pipe or pump. It is generally believed that the 
