PRACTICAL FORESTRY. 



By stuffing a piece of tow in gas tar, or placing cyanide of 

 potassium in the hole and closing the aperture the cater 

 pillar may be overpowered and destroyed. 



A bent wire has oft been successfully used in dislodging 

 the caterpillar. 



The Holly Fly (Phytomyza aquifolia). The foliage of the 

 holly is frequently very much disfigured by the grubs of 

 the holly fly, which burrow beneath the upper skin of the 

 leaves, feeding on the internal substance. This imparts a 

 blistered and discoloured appearance, and which, in the case 

 of ornamental varieties, is anything but desirable. Pro- 

 bably no great damage to the infested trees is brought about, 

 but the wholesale destruction of the leaves, as is often the 

 case, rannot but weaken the plant. 



In May and June the flies make their appearance, and lay 

 their eggs beneath the upper skin of the leaf, from which 

 the grubs, about ^ in. long, are hatched. These work 

 their way beneath the skin of the leaves, forming 

 small tracks of a more or less circular shape, thus causing the 

 large and unsightly blisters. They quit the leaves about 

 March, by making small holes in the skin of the leaf, and 

 afterwards become chrysalides. The fly is small and incon- 

 spicuous. 



Picking off and destroying affected leaves, or crushing the 

 grub by pinching the blisters are the only ways of lessening 

 the attacks. 



The Oak Leaf Roller Moth (Tortrix viridana) . The 

 widespread destruction caused to oak-woods in almost every 

 part of the country by the caterpillars of this little moth 

 would seem to be on the increase from year to year. But it 

 is not the oak alone that suffers, for numbers of the horn- 

 beam and beech are in an equally pitiable condition. Having 

 closely watched this insect for several years, mainly with the 

 view of striving to keep it in check or devise some means of 

 destruction, I have come to the conclusion that a few 

 individual trees may, at considerable expense, be got rid of 

 the pest, but in the case of whole woodlands artificial treat- 

 ment is quite out of the question. Many observers are 

 under the impression that the caterpillar is mosfc abundant 



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