452 Journal of Agriculture , Victoria. [lo July. 191 r. 



Inspector, by the other inspectors and myself show this to be the case. In 

 his report, Inspector Hammond states : — 



Owing to an improvement in the growth of the trees some time after the injection 

 of carbon fumes, it was erroneously attributed to the destruction of the borers at the 

 roots, but Massey jjoints out that, though the carbon fumes destroy the nitrifying 

 bacteria of the soil, they also destroy all the forms of bacteria, amongst which are 

 those that prey upon the nitrifying ones, and these latter, when again introduced, 

 multiply much more rapidly than the others, and stimulate the growth for a short 

 period. 



On 24th March I treated four Five Crown apple trees in the same orchard. I 

 made holes with a crowbar, as the injector would not put the carbon down suffi- 

 ciently deep. I had ascertained that, in soil such as the one being treated, no grubs 

 live within about 20 inches of the surface. T gave from iS to 21 injections to each 

 tree, using the Pal injector; g to 5 oz. of bi-sulphide being injected into each hole. 

 The holes were about 30 inches apart, and 20 inches from trunk of tree, and were 

 within a circle of about 9 feet in diameter. The quantity of bi-sulphide used .'or 

 each tree was from 6 to 105 ozs. 



On 25th May, about eight weeks later, I partly grubbed one of the trees treated 

 on 24th March. A careful examination of the soil and roots was made, and five 

 live grubs and one dead one were found. Three of the live grubs were nearly 

 full grown, one about half grown, and one very small. The dead grub was full 

 grown, and in a good state of preservation. None of the grubs were found nearer 

 than 24 inches to the surface. The dead grub was found 30 inches below the 

 surface. 



I partly grubbed two other trees, not treated, for the purpose of comparing them 

 with the one treated. I found four grubs and a beetle from 24 to 30 inches 

 below the surface in the clay in one tree, and one grub and one beetle were found 

 in the other. No dead grubs were found in the untreated trees, but, apart from 

 this, there was no difference in the appearance of the grubs. In this case the bi- 

 sulphide did little or no good as far as I could see. 



Inspector Cock, of Bendigo, has carried out experiments in root treat- 

 ment, by the application of bi-sulphide of carbon ; and, in addition, gas 

 lime, lime, cyanide of potassium, and cyanide of soda, with no appreciable 

 benefit . 



Arsenical Spraying. 



There is evidence that arsenical spraying is partially effective. Inspec- 

 tors Farrell and Hammond reported that they have found as many as 

 thirty dead beetles under trees sprayed with arsenate of lead, whereas prior 

 to the use of this material no dead beetles were to be found. Though 

 spraying may kill many of the beetles, it cannot, in my opinion, be regarded 

 as other than a factor, and probably a small one, in dealing with this 

 insect. Even if the beetles consume .sufficient of the sprayed foliage to get 

 a fatal dose, death in insects is always slow^ from arsenical poisons. 



The first thing that takes place on emergence from the soil is the copu- 

 lation of the sexes, so, even if the female were killed by poison, she would 

 be fertile, and probably able to eject her eggs (as many insects do when 

 dying from injuries, &c.), though too feeble to draw the leaf together to 

 protect them. On the othei hand, eggs are not fully developed when 

 beetles first emerge from the soil, and the beetles might be poisoned some 

 time before this happens ; but, notwithstanding that these creatures devour 

 large quantities of foliage, the vitalitv of all insects immediately previous 

 to egg-laying is remarkable. 



In order to be successful it would be necessary to sprav the fruit trees 

 during their period of growth, as well as all herbage throughout the entire 

 year. 



Bandaging. 



Bandages are of little use unless properly attended to and adjusted, as 

 the beetles are capable of walking up clean glass alm.ost as freely as up a 



