INSECTS INJURIOUS TO PINES. 77 



(ffylesinus, Hylurgus) piniperda The Retinias are small 

 moths belonging to the group Tortricina (Leaf-rollers), of oblong form, 

 reddish brown or grey in colour with somewhat elaborate markings of 

 paler stivnks and bands, assimilating in tint to the colour of Pine-bark 

 of different shades, a feature specially characterising Conifer-feeding moths. 

 By far the most important species in Great Britain is Retinia buollana, 

 though the scarcer R. turionella has got more credit as an injurious 

 species; it is equally destructive in habits. R. buoliana appears at the 

 beginning of July, R. turionella some three weeks earlier. 



Both moths lay their eggs singly on young Pines at the base of 

 the buds of the terminal shoot or lateral branches; into these the 

 caterpillars bore, hollowing out the centre bud, and then attacking the 

 lateral buds in the same way so as to destroy the whole or part of the 

 terminal whorl. The larvae live in the shoots through the winter, and 

 pupate there in the spring. Their presence is easily recognised by the 

 altered and stunted shoots which have failed to grow, and break off at a 

 touch, as well as by the flow of resin caused by the feeding. The effect 

 on the tree of the loss of the terminal shoot has been already mentioned; 

 the lateral branches injured by R. buoliana subsequently grow twisted, 

 and take on a characteristic curved " post-horn " shape which lasts for 

 many years after the injury. 



These insects suffer, fortunately, from the attacks of many parasitic 

 enemies, for practical treatment has met with little success. The 

 infested shoots have been persistently cut off and burned for many 

 years in succession without real benefit resulting ; this treatment is 

 only applicable to small isolated areas, and should be tried during the 

 month before the appearance of the moths. Egg-laying takes place in 

 the evening, and it is sometimes worth remembering that the moths 

 can be kept off small patches of trees which it is important to 

 preserve by lighting weed-fires to windward, so that the smoke will 

 drift over. This is not capable of extended application, but may be 

 employed to protect ornamental trees which sometimes suffer severely 

 in the neighbourhood of large Pine woods. These insects are most 

 troublesome when trees are crowded together, neglected, and grown on 

 unsuitable soil, and, as is usually the case, when the wood is not 

 mixed. 



Pine-beetle. Myelopliilus (Hyluryus) piniperda is, next to Hylobius 

 (iliii'ti*, the most injurious insect to Pines in Great Britain, over the 

 greater part of which it is very abundant. There are, however, many 

 districts where it does not occur, or has not been observed, but almost any 

 Pine-wood will yield evidence of its presence to a careful searcher. It 

 is a small oblong brown beetle of the family Scolytidce, or Bark- 

 beetles. 



The female, about the beginning of April, chooses a tree for 

 oviposition. Those selected are newly dead or dying Pines, especially 

 freshly felled timber, unbarked logs and stumps, or trees injured by 

 storms, snow, or fire. ( )ceasionally the beetle makes use of Spruce and 

 Larch. She commences boring under a projecting scale, where the bark 

 is thick, often on the under side of a fallen trunk, if it is free from 

 the ground, and excavates a gallery in the bast running, with the 

 exception of the entrance which is oblique, along the axis of the trunk. 

 It is from three to four and a-half inches long, and takes from three 

 to five weeks to construct. 



