3. ANIMALS INJURIOUS TO FOREST AND ORNAMENTAL 



TREES. 



THE LARCH AND SPRUCE CHERMES. 



Chermes abietis, Linn. 



I gave an account of this insect in my 3rd Report, tog-ether with 

 the recommendations of Mr. E. R. Burdon, 1 thanks to whom the pest 

 has been completely eradicated from many estates. 



It is important to again emphasise the necessity of winter spray- 

 ing before March. 



The injury occasioned by these insects is considerable. In this 

 country the spruce and larch are the chief sufferers, for not only do 

 the pines appear to be less attacked, but they seem better able to 

 resist the pest. Further, the diseased trees are less able to with- 

 stand the attacks of other insects which then take possession, laying 

 their eggs thereon, or burrowing into the decaying wood, and thus 

 hastening the death of the tree. Fungi also make their appearance, 

 and it has been pointed out by Professor Marshall Ward that diseases 

 such as the Larch Canker no doubt often gain an entrance into the 

 trees through the wounds made by Clienucs and other insects. The 

 Larch Leaf Rust and Spruce-Shoot Disease are also probably so intro- 

 duced. Mr. Burdon points out that the hyphae of the fungi are always 

 found in the old galls on the spruce, while the black, bead-like fruit 

 bodies may be seen projecting from the stomata of the leaves, viz., 

 the apices of the needles of the dead gall. 



PREVENTIVE AND REMEDIAL MEASURES. 



The methods recommended by Miss Ormerod, Mr. Blandford, 

 and others the snipping off of the galls in the summer is both 

 troublesome and unsatisfactory, for it not only damages the trees, but 

 does not lessen the pest. This is, of course, intelligible when the facts 

 of the life-history are considered, since the supplies on the spruce are 

 kept up by the return of adult winged forms from the larch. Experi- 

 ments go to show that this drastic treatment is often more serious 

 than that caused by the insects. 



13rd Report Inj. Insects, 1906, p. 14. See also Burdon : Journ. Econ. Biol., 1907, vol. ii, pp. 64-67. 



