209 



Summary. 



The writer agrees with Froggatt (1922, p. 20) that the solution of the 

 AustraHan sheep maggot-fly problem lies in the destruction of the fly before 

 it has had an opportunity to deposit eggs or larvae on living sheep. Extermina- 

 tion cannot be hoped for, but fly control is not only a possibility but a necessity 

 under present conditions of sheep raising. 



Fly control can be most successfully established by systematic destruction 

 (by burning or poisoning) of carcases and carrion. Co-operation amongst sheep 

 owners is essential, as neglect on one sheep-raising property may easily lead to 

 infestation in a neighbouring "station" as well, since it is known that blowflies 

 can tra.vel with, against, and across the wind for many miles in a very short time. 



Of secondary importance as a means of controlling flies is the utilization 

 of traps for the adult insects and of various chalcids which attack either the 

 larval or pupal stages of such flies. Published evidence in regard to the value 

 of N^asojiia in this connection is rather conflicting. 



The preservation of insectivorous and carrion-feeding birds is highly 

 desirable. 



Experimental work in Queensland has demonstrated the value of applica- 

 tions to the sheep of strong arsenical solutions as a means for destroying any 

 maggots and other external parasites already present, and for affording a very 

 marked measure of protection for periods of from six weeks to three months, 

 such application being made especially in the form of "jetting," or else in the 

 form of showering, dipping, or swabbing. Such treatment may be accompanied 

 by crutching in order to clear away the "dags" and soiled wool. 



It is suggested that bacterial activity may be the prime factor in inducing 

 blowfly attack, and that the arsenical treatment may owe its protective efficacy 

 to its bactericidal action. 



It may be advisable for sheep breeders to dispense with wrinkled sheep, as 

 they are most liable to infestation. It may be necessary to breed a type of animal 

 carrying very little wool on the breech. It is well known that crossbreds are less 

 liable to infestation than are merinos. 



A change in the time of shearing may be advantageous in order that the 

 sheep may not carry a heavy fleece during the season when fly attack is most 

 likely, i.c^ during autumn and spring. 



References. 

 Brown, W. G. — 



1919 — Sheep Fly Investigations (Report of Queensland Special Committee). 



Science and Industry, 1, pp. 63, 64. 

 1919— Queensland Agr. Jour., Feb., 1919. 



Cooper, W. F. — 



1913 — The Sheep Maggot Pest in Australia, 88 pp. Contains Essays by 

 Froggatt (pp. 10-48), Woodburn (pp. 49-54), McLeod and 

 Holme (pp. 55, 56). 



Cory, A. H., and Jarvis, E. — 



1913 — Reports on Investigations into the Sheep Maggot-fl.y Pest (pamphlet). 

 Dept. Agric. Q'land, 1913. (Jarvis' report, pp. 8-16.) 

 Editor — 



1921 — The Blowflv Pest. Demonstration at Dalmally. Q'land Agr. Jour., 

 June, 1921, pp. 249-253. Rev. Appl. Ent. B., 9, pp. 156, 157. 



