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Adkin (B. W.)- The Practical Aspect of Forest Entomology. Part IV. 



—QrtJij. JI. Forestry, London, xii, no. 2, April 1918, pp. 80-9S. 



This paper deals with insects that are known to be highly injurious 

 to coniferous woods and plantations in Britain. Hylobvus abietis 

 (large pine weevil) is considered the worst of these, and is very wide- 

 spread, hardy and j)rolific. Hundreds of acres of pine and spruce 

 are at present being felled, which it is desired to re-plant with, young 

 conifers. It is pointed out that if this is done while the old stumps 

 are left in the ground without treatment, the weevils will breed freely 

 in them and will devour the bark of the young trees. Suggestions 

 are made regarding a change of crop until the stumps have decayed, 

 but it is j)ointed out that this will not check the increase of the weevils, 

 which will probably migrate elsewhere. Recommendations for treat- 

 ment of the old stumps are given, the most successful being hot 

 creosote, the cost working out at a little over |d. per tree. Trapping 

 the weevils, and encouraging the destruction of the larvae by means 

 of the parasite Bracon hylobii, Ratz., are supplementary measures. 



Myelophilus (Hylurgus) piniperda (pine beetle) is a dangerous pest, 

 persistently boring the growing shoots of older jjine trees so that in time 

 they succumb. The chief methods of control are the elimination of 

 breeding-places, or the provision of breeding-places as traps in which 

 the beetles may be destroyed. This can be done by barking the logs, 

 not later than May, and burning the bark. 



Sawflies of larch and ])me may cause great havoc by stripping the 

 foliage of conifers. Pine-shoot moths include some ten species of the 

 genus Rhyacionia {Retinia), such as R. huoliana, R. pinicolana and 

 R. turionana, the larvae of which bore into the buds at the end of pine 

 shoots, particularly on young trees. Coleophora laricella (larch 

 mining moth) is found in many districts in Britain, the larvae boring 

 into the needles in July and causing them to shrivel and turn white ; 

 here they pupate and the adults oviposit on the young shoots in the 

 spring. Blastotere {Argyresthia) atmoriella, Bnks. (larch twig-boring 

 moth), which, was formerly erroneously recorded in England as 

 A. laevigatella, H.S., attacks larch in many districts. 



Various Apliids attack roots, foliage, buds, twigs, branches and stems 

 of trees, sucking the juices and w^eakening them. Any nursery stock 

 showing infestation with Aphids should be jDroperly fumigated before 

 planting out. Some conifers, such as Corsican j)ine, Sitka spruce and 

 Japanese larch, are comparatively immune to Aphid attacks. 



The general lines of procedure that are found most successful in 

 preventing or checking the attacks of injurious insects include the 

 destruction of all rubbish after felling, the elimination of breeding- 

 places for those insects that pass their larval stage beneath the bark 

 of stumps, felled trees, dead wood or- sickly trees. Trees should be 

 maintained in robust health and vigorous growth, so that insect 

 attack may be avoided, or recovery after attack assured. Any 

 assistance given by nature in this respect should be encouraged, such 

 as protecting insectivorous birds in the woods and plantations, and 

 rearing or importing parasitic enemies of the pests. 



With regard to the first recommendation, this may be difficult to 

 carry out while thousands of acres are being felled during the War, 

 and while labour is scarce, and it is feared that insects that usually 



