264 CONIFEROUS TREES 



severely, whereas in an adjoining section, and 

 apparently under similar conditions, not a vestige 

 of the pest can be detected. 



It is a small dark grey moth, less than a quarter 

 of an inch long ; while the caterpillar is about 

 the same length, of a dirty yellow colour, the head 

 being black. The larva burrows beneath the bark 

 of the younger shoots, and finally works its way 

 to the centre of the stem, causing the death of 

 the affected part. Several preventive remedies 

 have been tried in the case of single trees, such as 

 spraying in early May, at which time the eggs are 

 deposited on the young shoots, with petroleum 

 emulsion. Smoke from burning branches has 

 been successful in restricting the attacks of the 

 insect, but in the case of a whole plantation such 

 remedies are out of the question. In thinning a 

 plantation, removal of as many injured trees as 

 possible is recommended, and in the nursery 

 pruning off affected shoots has had good 

 results. 



Tree Wasp or Giant Sirex {Sirex gigas) is one 

 of the most persistent and injurious of boring 

 insects, attacking the Scotch Pine and sometimes 

 the Larch. It is a beautiful insect, i inch long, 

 of a black colour relieved by golden bands. 

 Generally, felled trees, or such as are some- 

 what sickly, are chosen by the female in which 

 to lay her eggs. These are deposited beneath 

 the bark by means of the powerful ovipositor, 

 and in course of time the whitish cylindrical 

 maggots make their appearance. The maggots 

 feed in the solid wood, making holes that are 

 about a quarter of an inch in diameter by means 



