CHAPTER IX. ' " ?v.V#/V 'u- 



ENEMIES OF CONIFERS. * ^ ' ^ . 



(l) Insects. 



Several species of coniferae are at times attacked by insect 

 pests, the following being a list of such as have been found 

 most injurious, with an account of the trees they infest, and 

 the best known means for their extermination. 



Pine beetle {Myelophilus piniperda). This beetle at- 

 tacks the Scotch pine {Pinus silvestris)^ the Corsican {P. 

 Laricio\ the Austrian (/*. Laricio austriaca), and the Aleppo 

 {P, halepensis). I have also known it to attack the spruce 

 {Picea excelsa) and the Weymouth pine {P. Sirobus)^ but 

 very rarely. At Kew, both Pimis muricata and P, insignis 

 have been attacked by this beetle. The principal injury done 

 by this insect consists in the destruction of the leading shoots 

 of the tree it attacks. It bores into the side of the shoot till 

 it reaches the pith, then tunnels upwards, making an exit at 

 the terminal bud. This tunnelling so weakens the shoot that 

 it is easily broken over during stormy weather 



During the summer months June, July, and August the 

 beetle is most abundant. The beetle is propagated in dead 

 and dying wood ; old stumps are also favourite breeding- 

 places. 



Unfortunately it is not only unhealthy trees that are 

 attacked by this insect, for I have had to deal on several 

 occasions with the attacks on rapid-growing specimens of 

 several species of Pinus. The insect is greatly on the increase 

 in this country, and during the present season the plantations 

 in Forfarshire, Bedfordshire, and other parts of the country 

 have suffered to an almost alarming extent from its attacks. 



175 



