Sept .'2, 1920.] Agricultural Gazette of N.S.W. 



Spraying as a Preventive for Blow-flies* 



Trials at Trangie Experiment Farm. 



A. H. MacDOUGALL, Manager. 



[The Experiments Supervision Committee, under whose control these experiments are 

 being conducted, wish to draw attention to the fact that final conclusions cannot yet be 

 drawn from these trials, as they have only been conducted for two years. They are 

 published now, it being recognised that the public are entitled to know the results 

 obtained.] 



The experiments in connection with the prevention of blow-fly attacks on 



sheep were continued this year, the same specifics being used as in previous 



years. The sheep used in the trials were .342 flock Merino breeding ewes 



that had been mated during November and December, 1919. They were 



divided into four groups, the treatment of the respective groups being as 



follows : — 



Group 1. — Eighty-six sheep treated with a proprietary powder dip 



containing arsenic and sulphur. 

 Group 2. — Eighty-six sheep treated with I lb. arsenic to 50 gallons of 



water. 



Group 3. — Eighty-five sheep treated with a proprietary liquid dip 



having carbolic acid as its basis. 

 Group 4. — Pjighty-five sheep not treated, as a basis of comparison. 



The sheep were sprayed in a race specially constructed for the purpose, a 

 hand force-pump with hose and nozzle being used. The sheep were sprayed 

 three times, viz., on 7th November, 30th December, and 10th February. 

 At the first spraying two pints of each mixture were used on each sheep, at 

 the second spraying two and a half pints, and at rhe third three pints. This 

 increase was necessitated by the increase in the quantity of wool that had 

 to be saturated on the second and third occasions. The blow-fly commenced 

 to be active early in March, but as the sheep were then in poor condition 

 and forward in lamb, no further spraying could be made. 



During the latter end of March and the whole of the months of April and 

 May, the flies were very numerous, and could hardly have been worse. In 

 the stud flocks on the farm, men were daily employed solely dressing blown 

 sheep. 



The sheep used in these trials were allowed to go without treatment until 

 it was necessary to treat them to save their lives. 



It was observed that once a sheep was struck the dressings used appeared 

 to make no difl'erence in the way of reducing their destructive progress or 

 their numbers. The benefit derived by the treatments appeared to be in the 

 prevention of attacks, and in this respect the carbolic dip used on Group 3 

 stood out as the best used in the trials. 



