172 PROTECTION OF WOODLANDS. 



As already remarked, this Spruce moth also attacks broad- 

 leaved species of trees, Beeches, Birches, and fruit-trees, and even 

 feeds on the leaves of whortleberry bushes occurring as under- 

 growth under trees that have already been denuded of their foliage 

 by the voracious caterpillars ; but the damage done is, thanks to 

 the greater reserve-supplies of nourishment stored up in the 

 broad-leaved deciduous species, never of a fatal nature, as is not 

 unfrequently the case with the conifers. 1 And in Spruce woods 

 particularly, bark-beetles follow soon after the attacks of this 

 caterpillar, for the sickly stems afford the most favourable 

 breeding-places for these other most dangerous insect enemies 

 (vide note on page 128). 



True preventive measures can hardly be said to exist for 

 hindering attacks of this dangerous moth, but the early discovery 

 of its presence and the immediate adoption of annihilative mea- 

 sures may promptly exterminate the brood, and easily obviate 

 disastrous calamity on an extensive scale. If the woods are as 

 carefully and constantly inspected as they should be, then the 

 presence of the characteristic fragments of bitten leaves and needles 

 scattered about the ground, the gradual thinning of the crown of 

 foliage, and later on the light-coloured and easily distinguishable 

 moths seen during the time of swarming in summer, ought to 

 leave no doubt as to the advisability of taking measures to prevent 

 their rapid increase in numbers. 



Exterminative remedies of various kinds are applied. First of 

 all, the ova may be collected at any time during August till April, 

 but this is of course only effective so long as the insects have con- 

 fined themselves to ovi- deposition near the base of the stem, the 

 clusters of eggs being scraped off with a knife into a bag held 

 below them. Although great numbers of ova can thus be 

 collected, yet at the same time many clusters of eggs get over- 

 looked, especially oh the thick-barked Scots Pine ; and the larger 

 the number of moths previously, the more likelihood there is of 

 the clusters being in great part deposited too high up the stem to 

 be within reach, so that on the whole the results of this method 

 are at best only partial and somewhat unsatisfactory. 



The crushing of the little schools or colonies of tiny caterpillars, 



whilst they are collected together for a few days just after coming 



out of the shell, is somewhat more practical and satisfactory; still 



1 And more especially so with regard to the Spruce. 



