Departmental Activities. 301 



DEPARTMENTAL ACTIVITIES 



February, 1921. 



(Note. — The work of the several Divisions and Schools of Agriculture covers a vi'ide 

 range of agricultural industry in the Union, and we give hereunder notes and observations 

 from certain of them treating with matters of special interest coming under their purview 

 during the month. The object of these notes, which are not concerned with general routine 

 work, is to inform the farmer of such matters as are calculated to be of interest and helpful 

 to him at the present time. — Editor.; 



THE DIVISIONS. 



ENTOMOLOGY. 



The Sheep Blow- fly. — One of the principal stock problems in 

 Australia of recent years has been the control of the sheep blow-fly. 

 The losses from this pest have been enormous. Unfortunately, it is 

 not altogether unknown in South Africa, and several correspondents 

 of the Division of Entomology have suggested that the trouble is 

 upon the increase. The Division has been in communication with the 

 Queensland authorities with a view to ascertaining the progress in 

 the investigations in hand there, and, as a result, has been favoured 

 with the following suggestions for the solving of the problem, made 

 by the Queensland Special Blow-fly Committee of the Commonwealth 

 Institute of Science and Industry. 



The jetting of sheep mentioned is accomplished with a high- 

 pressure spray pump delivering a solid jet of fluid. The poisonous 

 dip referred to is believed to be one well known on the South African 

 market, but here we would use five pounds of arsenite of soda in 

 place of the arsenic and carbonate of soda recommended. 



" These suggestions are the outcome of seven years' investigations .... The problem is 

 a very complex one. It has been found, for instance, that out of somewhere about forty-nine 

 specifics used as preventives most were laseless, some fairly efEective, and several effective 

 for a longer or shorter period. It has been found, too, that sometimes a specific has been found 

 effective in one season and useless in another. 



"Sick or wormy sheep are more susceptible to blowfly attack thanlhealthy animals. It is 

 wise, therefore, to keep the flock healthy. In the case of wormy sheep, they may be drenched 

 two or three times, with an interval of seven days, with arsenic and cpsom salts. 



"Segregation of flyblown sheep should be always carried out. It is found that 'once 

 struck, always in danger' applies most certainly even in a moderately mild attack. We 

 consider that stricken sheep should be drafted off from sound sheep at the beguming of the 

 fly season. 



"It has been estimated that even one dead sheep at watering places, camping grounds, 

 etc., will breed as many as 10,000 maggots, and is consequently quite sufficient to stock a 

 large paddock with flies within a month or six weeks. Therefore, where practicable, all 

 carcasses should be destroyed at such places as sheep congregate. 



" The Orion Downs method of jetting a poisonous solution into the breech of the sheep 

 has been found very effective up to two and a half to three months. This was proved at 

 Gindie, where the Orion Downs formula of four packets of poisonous dip to 100 gallons of 

 water was used. But it was evident that the sulphur was in excess in that proportion of 

 dip, and as it appeared to us that it was the arsenical content of the various dips which was 

 the chief factor in poisoning the wool, it was decided to use only one-fourth quantity of the 

 Orion Downs formula to 100 gallons of water, sttpplemented by the addition of 4 lb. of 

 arsenic dissolved by 8 lb. of carbonate of soda, boiled for three-quarters of an hour in a 

 sufficient amount of water, say 5 gallons. This formula was used at Dalmally in April, 1920, 

 in the form of a jet at 100 lb. pressure. Not one sheep in about 3000 ewes was struck until 

 July, the flies laeing very active everywhere, thus putting the ewes over lambing without 



