184 PROTECTION OF WOODLANDS. 



E. LEAF-MOTHS (Tineidw). 

 87. Tlie Larch Mining-moth, Tinea (Coleophora) laricella. 



This very small, greyish-black moth swarms about the end of 

 May or the beginning of June, the female laying her eggs singly 

 on the needles of Larches from about the pole-forest stage of 

 growth onwards, whilst saplings and plants of younger growth are 

 only exceptionally attacked after the insect has increased greatly 

 in numbers. 



When the tiny caterpillar makes its appearance after being 

 about 3 to 4 weeks in the ovum, it bores its way into the needle, 

 eats out the contents of the spine, makes use of the empty shell as 

 a protective covering, and then hibernates in this little, yellowish- 

 brown sack, which is firmly attached to the twig. In the 

 following spring it resumes feeding on the soft fresh needles, but 

 still drags its original sack about with it, and finally enters the 

 chrysalid stage in this. The new flush of foliage attacked be- 

 comes yellow and withered at once, and the injuries inflicted often 

 assume such dimensions, especially on young Larch trees near the 

 edges of the compartment, that hardly a sound tuft can be seen, 

 the foliage looking as if it had been nipped and damaged by late 

 frost. They gradually, however, recover, as new tufts of needles 

 are formed in the centre of the damaged rosettes, and numerous 

 short shoots develop, which assume the functions of the original 

 long shoots that have been destroyed. 



These injuries are often inflicted year after year on young 

 Larch trees growing near the edge of compartments, and of course 

 then do a great deal of damage, not only retarding them 

 materially in their development, but also killing them off finally. 

 Borggreve considers this mining-moth one of the chief primary 

 causes of the cankerous disease so frequently noticeable on young 

 Larch stems. 1 



Annihilative measures can hardly be applied against this tiny 

 little insect. Large numbers of the caterpillars are devoured by 

 tomtits, and destroyed by Ickneumonidce, whilst heavy showers of 



1 The generally accepted opinion among sylviculturists throughout Germany is 

 distinctly that the primary cause of the Larch canker is the fungus Peziza Will- 

 kommii, R. Hrtg. , although of course there are several predisposing iniluencos. Careful 

 selection of soils and situation suitable to the Larch, and the formation of mixed 

 rather than of pure crops, are the sylvicultural means of decreasing the dangers with 

 which this tree is threatened in Britain. Trans. 



