Locusts : Season 1921-22. 



223 



Destruction or Flying Swarms. 



Every encouragement has been given and every effort made to 

 get the farmers to destroy as many as possible of the flying locusts, 

 and quite a large amount of destruction has been effected. The natives 

 are known to have collected thousands of sacks of flying locusts, 

 chiefly in the Maf eking, Vryburg, and northern Transvaal districts. 

 Several suggestions have been put forward for destroying the flyers, 

 the most popular of which is the use of aeroplanes. Inquiries made 

 at the Defence Force Headquarters, however, elicited the fact that, 

 though aeroplanes might be used to advantage from a scientific point 

 of view, i.e. for the purpose of following up the swarms, from a 

 destructive point of view their use was impracticable for the following 

 reasons : (a) An aeroplane can remain in the air continuously for 4J 

 hours only ; (6) an aeroplane can only land on prepared ground ; landing 

 grounds would, therefore, have to be surveyed and constructed at 

 various centres, and then the locusts would not always oblige by flying 



Loading Poisoned Bait in the Midlands, C.P. 



in the direction of the landing places; (c) no effective weapon for 

 fighting the locust from an aeroplane is available ; gas bombs and 

 liquid fire would be equally useless and purely local in eff'ect ; (d) aero- 

 planes could not fly through locusts : the propeller would be promptly 

 damaged and the machine put out of action ; (e) the expenditure 

 involved in connection with the running expenses (£4 per hour), con- 

 struction of landing places, erection of petrol and oil depots, equip- 

 ment, etc., and the very small amount of damage that can be caused 

 to a swarm of locusts from an aeroplane, do not justify its use for the 

 purpose of destroying locusts. 



Experience has proved, however, that the most effective method 

 of destroying flying swarms of locusts is by spraying them with poison 

 while they are resting at night or in the early morning. A large 

 amount of damage to flying locusts has been carried out in this manner 

 during the past season. 



Natural Enemies to Locusts. 



The flies and birds caused a considerable amount of damage 

 amongst the locusts; the latter, however, would have rendered far 



