366 



FOREST ENTOMOLOGY. 



The life-history of this species does not appear to have been worked 

 out, but it would well repay any one to follow it out. 



As regards any remedial measures, it would perhaps be best to 

 collect (by clipping off) the individual injured leaves while they 

 remain in the young stages, and such clippings should be burned. 

 In its younger stages the ash is a tree which is somewhat difficult 

 to grow to perfection in the nursery, but more especially in the young 

 woods. Hence it is well to encourage vigorous growth. The seed- 

 lings should be transplanted at a year old and grown for two years 

 in the nursery-lines, and then either transplanted in the nursery or 

 otherwise in the young woods, under the protection of wire-netting, 

 and if possible also under the sheltering influences of more hardy 

 species planted in advance. If they are transplanted in the nursery- 

 lines as one year, two years old, or say 18 to 24 inches in height, 

 they should be quartered the following year that is, the best plants 

 should be taken out, and so thin the crop that " spindling " is pre- 

 vented in those which remain. The latter class should then make 

 very useful trees for park planting, where a method of systematic 

 groups at regular intervals, for continuity of effect, is the object in 



view. If, on the other hand, two-year 

 seedlings are transplanted in the nur- 

 sery, then it is often advisable to grow 

 for one season and cut the plants down 

 the following year close to the ground, 

 taking care that only one good, strong, 

 vigorous shoot will spring up. Atten- 

 tion to these practical points, together 

 with any improvement on them, is 

 the best antidote against any appreci- 

 able damage accruing from the in- 

 juries of the insect in question. 



Fig. 341. Leaves of box injured by 



Psylla buxi. 

 a, normal leaves ; b, injured leaves. 



Psylla buxi (Linn.) 



This insect in its larval stages, and 

 also in its early adult stages, causes the 

 leaves of the box to curl up, so as to give rise to a sort of pseudo-gall, 

 as seen in fig. 341. Fig. 341 (a) represents the normal twigs of box 

 leaves, and fig. 341 (b) shows the "galls" caused by the insects. 



