274 A HANDBOOK OF CONIFER.E 



be found in June, Eggs are laid on the leaves and the cater- 

 pillars hatch out in July. They first bore into the leaves, causing 

 the upper half to shrivel. Each larva then forms for itself a case 

 of dead leaves lined with silk, the case appearing as a tiny cigar- 

 shaped body. When the larva is feeding the case is seen in an 

 erect position with the head pointing downwards. The larvae 

 feed until autumn, then hibernate in bark crevices until spring. 

 As soon as young leaves appear the larvae recommence feeding 

 and continue until they pupate. Trees injured by this moth 

 appear as if they had been badly frost-bitten or scorched by fire. 

 No practical means of coping with the pest is known. 



Argyresthia atmoriella, Banks ^ (Larch-shoot Moth). This 

 small moth lays its eggs at the lower part of the current year's 

 shoots during late May and early June. The caterpillars bore 

 into, feed upon the shoot, and hibernate in it during winter. In 

 early spring the larvse recommence feeding and continue until 

 ready to pupate. The shoots are weakened or killed and growth 

 is checked in consequence. In other countries two other moths, 

 Argyresthia Icevigatella, Zeller, and A. zelleriana, Hartig, affect 

 larch in the same way, 



Dasyscypha calycina, Fuckel (Larch Canker Fungus), This 

 fungus has caused great destruction amongst larch trees in Britain 

 and other countries. Although it is rarely absent from young 

 plantations of common larch the attack may be slight and cause 

 little harm, or almost every tree may be seriously affected. Trees 

 growing on high, well- drained land are less liable to the disease 

 than those at a low elevation or on wet soil, and trees over 

 eighteen years of age are rarely injured. The fungus can only 

 gain entrance to the trees through wounds, and the spores often 

 germinate upon wounds caused by frost or the punctures of 

 Chermes laricis and other insects. The only way to avoid the 

 disease in its more serious forms is to confine plantations to suit- 

 able positions and soils, where the natural vigour of the trees 

 enables them to overcome an attack. Some good can be done 

 in preventing the spread of the disease by planting larch in 

 mixed instead of in pure plantations. European larch is more 

 subject to injury than Japanese larch, although the latter is not 

 immune, as is sometimes suggested. 



Meria laricis, Vuillemin, causes the premature fall of the 

 leaves. The fungus occurs as tiny white specks of mould, and a 

 severe attack is followed by considerable browning of the leaves, 



Bhizina inflata, Karsten, is parasitic upon the roots of several 

 species of young coniferous trees, including larch. Badly in- 

 fected trees usually have a large mass of mycehum and soil 

 about the junction of the stem and upper roots ; later on, cushion- 

 like fructifications appear. Diseased trees should be burnt, and 



1 Ministry of Agric, and Fish, Bull, 208 {Larch-shoot Moths). 



