BRITISH FOREST TREES 61 



Liability to suffer from External Dangers is un- 

 fortunately characteristic of the Scots pine at all stages of 

 its growth. In its earliest years it is apt to suffer seriously 

 from the larvae of species of Agrotis and Gryllotalpa at time 

 of germinating, then of Melolontha gnawing the roots, whilst 

 the bark is attacked by the fully developed weevils of 

 Hylobius and Pissodes species. The cortex and sap-wood of 

 young plantations suffer through the larvae of Hylurgus, 

 and those of poles and trees from Bostrychus, Hylurgus, 

 Hylastes and Polygraphus ; Gastropacha and Retinia cater- 

 pillars often decimate the buds ; young shoots are badly 

 damaged by species of Hylurgus and Retinia ; and finally the 

 leaves form too often a favourite grazing ground for the 

 caterpillars of Gastropacha pini, Liparis monacha, Trachea 

 piniperda, Fidonia piniaria, Lophyms pini and Lyda 

 pratensis. 



Leaf-shedding^ or the loss of foliage, a fatal disease to 

 which Scots pine is liable, and particularly so at the 

 age of three to five years, is caused by drought (according 

 to Ebermayer), or by frost (according to Nordlinger), or 

 (according to R. Hartig), in many cases either by a process 

 of drying up due to transpiration through the leaves on 

 sunny days in winter whilst the frost-bound soil can yield no 

 supplies of moisture to replace that evaporated, or else by a 

 fungoid disease from infection with Hysterium pinastri.^ 



From fungoid diseases, too, the Scots pine has to bear 

 somewhat more than its fair share. The leaves of young 

 seedlings are attacked by Hysterium pinasiri, and sEcidium 

 pini, the branches and stems of poles and trees by Trametes 

 pini, sEcidium pini, and Cccoma pinitorquum, and the roots 

 and base of the stem by Agaricus melleus and Trametes 

 radiciperda, whilst cotyledons and leaves of seedlings 



1 K. Ilartig's Lehrbnch der Kanmkrankheiten, 2nd edition, 1889, 

 1>1>. 103109. 



