1908.] 



Large Larch Saw-Fly. 



659 



solution through a fine wire gauze to divide it finely. But 

 a still more effectual method of destroying the younger larvae 

 is to crush them with a gloved hand. For this method to be 

 carried out rapidly and to secure the best results, the larvae 

 must be carefully watched until they reach the stage where 

 they congregate in masses, that is, about the third and fourth 

 larval stages ; in this stage of the life-history I have counted as 

 many as sixty larvae in a single mass, all of which could be 

 easily destroyed by a single closing of the hand. If they are 

 dealt with in this manner a number of men can quickly clear a 

 plantation of young trees from five to eight years of age. Spray- 

 ing might be restricted to the slightly older trees whose upper 

 branches are out of reach. Hand-picking also proved very 

 effectual in the case of young trees. 



In the older plantations it is necessary to rely on natural 

 means of control, such as have been mentioned already. Some 

 natural means of control, however, can be assisted and aug- 

 mented, and such is the case with regard to the birds which 

 have been mentioned as feeding on the larvae ; chief of these 

 are rooks, starlings, jackdaws, and tits. In the districts where 

 the trees are badly attacked these birds should not be destroyed 

 on any account. The starlings and tits should be encouraged 

 and protected by feeding them during the winter and thus 

 preventing the customary great mortality which results from 

 hard weather, and also by the provision of nest-boxes in the 

 plantations. Larch plantations are singularly devoid of suitable 

 nesting places for these birds and they should therefore be 

 supplied. In England these insectivorous birds are not 

 sufficiently encouraged in places where nesting sites are absent 

 by the provision of nesting boxes, the value of which form 

 of forest protection has been recognised for a number of years 

 in Continental forests. The best type of nest-box is that 

 designed by Baron von Berlepsch.* 



As the Field Vole, M. agrestis, has been shown to be an im- 

 portant means of control by destroying the larvae in the cocoons, 

 it would be in the interests of the forester not to destroy the vole 

 until the saw-fly attack shall have subsided. If it is found 

 that they are increasing to any alarming extent and attacking 



* " How to Attract and Protect Wild Birds," by M. Hiesemann. Translated by 

 Emma S. Buchheim. London : Witherby, 1908. 



