1 6 REPORT ON INJURIOUS INSECTS FOR 1905. 



withstand 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 Chermes 

 and other insects. The Larch Leaf Rust and Spruce-Shoot 

 Disease are also probably so introduced. 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. Experiments go to show that this drastic treatment is 

 often more serious than that caused by the insects. 



Miss Ormerod also recommended " drenchings with any of 

 the Aphis washes in July or when the Chermes are seen to be 

 hatching," but Mr. Burdon points out that the majority of the 

 galls are closed in July, in consequence of which the fluid would 

 not reach the occupiers, and would therefore be of no effect. 



Mr. Blandford has suggested washing in April, which would 

 certainly destroy numbers of the mothers and eggs, but would still 

 prove ineffective if the season was early and the larvae had com- 

 menced to enter the galls. 



It is quite evident from Mr. Burden's researches that the winter 

 mothers or foundresses must be removed whilst still in the hiber- 

 nating condition : it is therefore all-important that any washing 

 should be done in the winter. The results from Mr. Burden's 

 experiments were most satisfactory. He used a spray fluid con- 

 sisting of I Ib. of paraffin, \ Ib. of soft soap, and 8 gallons of 

 water. Taking a shoot on which the buds were badly infected, it 

 was dipped into this fluid, all parts being thoroughly wetted. 



In the first experiment, six shoots bearing a total of twenty- 

 four infected buds, with thirty-nine Chermes on, were so treated. 

 All the insects except one died, and twenty-three of the buds 

 developed into strong, healthy shoots, showing no sign of gall 

 formation. A single foundress that survived never appeared quite 

 healthy, and caused only a small insignificant gall. 



The second experiment was made at the beginning of April, 

 when the insects were awakening from hibernation, and had not 

 affected the buds to any extent. On six shoots bearing twenty 

 infected buds there were twenty-four winter mothers, all of which 



