8 May, 1907.] Fruit Flies. . 309 



Xorthern districts, wliere, owing to a congenial climate, the pest would 

 surely spread with great rapidity, and the aljsolute ruin of many of our 

 fine orchards would speedily follow. 



The fruit flies, as far as we are aware, have not become permanently 

 established in Victoria, but it would be well to see what others, who have 

 been less fortunate in this respect, have done towards the well-nigh hopeless 

 task of eradication. I am again indebted to Messrs. Froggatt and Tryon 

 and others for the results of their experiences in this direction. The 

 remedies referred to by Mr. Tryon I am inclined to agree with, and 

 amongst other methods mentioned in the preventive stage, that is, to pro- 

 tect uninjured fruit from attack, I may quote the following: — 



In Western Australia, the plan of placing kerosene boxes, in which 

 kerosene lias been placed, in the trees, has, so I am informed, pro- 

 duced the best results, no' fewer than some thousands of the flies having 

 been captured by these simple and inexpensive traps. Another method as 

 supplied tO' me is as follows: — "Place three or four small tins (sardine 

 tins being the best) in each tree, and pour a little kerosene in them. Let 

 the tins be on an incline so that a portion of the bottom of the tin is bare, 

 CT free from kerosene. A good plan is to nail the tins by the lids left 

 on the O'Ue side to the trunks and branches. The kerosene seems to attract 

 the flies." 



All fallen fruit should be destroyed by burning or boiling, in order to 

 prevent the lar\-3e from going into the ground to change intO' the perfect 

 insect, if this is not done immense numbers of flies wall be bred from the 

 infected fruit. Fine netting may also be used to cover a few trees, but 

 this in large orchards would, of course, be too expensive. 



The flies can no doubt be kept awav also by offensive odours of differ- 

 ent kinds, as preparations of tar, carbolic acid, &c., but this latter could 

 only be done some weeks before the fruit ripened. Mr. Tryon also re- 

 commends that wood-tar smeared on pieces of rag or tan and hung sus- 

 pended in the trees be adopted ; and I have no doubt as to the value of 

 this recommendation. The Italians have mixed w^ood-tar with soda 

 crystals, making a perfect solution for spraying, a s\ stem which ^\r. Trvon 

 informs me has lately been published. 



The shelly covering of the chrysalis renders it practicallv impervious 

 to any liquid application, but if the ground is dug up or raked, so that the 

 chrysalis is exposed, it dries up and dies. When the fruit drops to the 

 ground, it is virtually caught in its own trap. Then is the orchardist's 

 opportunity. If the infested fruit is gathered at least daily and de- 

 stroyed, the development of another batch of flies is prevented. Burning 

 o" scalding would be most effective, but as this is not always a convenient 

 method, it w'ould be well to keep an open trench about three feet deep in 

 which the fruit should he buried and a covering of the earth rammed down. 



Another effective way, as Mr. Tryon thinks, would be to place between 

 the trees some caustic substance which would destroy the tender maggot, 

 and he has found ordinary gas-lime and muriate of potash very efficacious. 

 Gas lime should be spread to a depth of one inch. 



Dr. Cobb, who has had many opportunities of dealing with the pest 

 in New South Wales, is not enamoured of the system as above recommended, 

 and counsels constant cultivation so as to kill the grubs and pupae below 

 ground. 



Finally then, the only effectual plan is to carefullv examine the growing 

 fruit, also any which may be sent to the Melbourne markets from affected 



