Introduction to the anti-tsetse fly operations conducted by the SAAF with fixed wing aircraft:

Excerpts from the third Van Ryneveld lecture of the South African Branch of the Royal Aeronautical Society 1975 by Maj. Gen. J.N. (Jack) Robbs.

From August, 1946, to December, 1951, the South African Air Force conducted spraying operations against the tsetse fly in Zululand and the Pongola area, of south eastern Swaziland, using converted Anson bombers and later Sikorsky S-51 helicopters as spray machines. The tsetse fly area of South Africa was isolated from the tsetse fly belt in Central Africa by some 450 miles and the operation resulted in the elimination of the fly (and its decimation of domestic animals) from South Africa. In the third van Ryneveld lecture to the Southern Africa division of the Royal Aeronautical Society, Major-General J.N. Robbs, 0.C. of 12 Squadron at Mtubatuba, Zululand, during the “anti-nagana” * campaign, described the techniques used in "this little publicised episode in the history of the South African Air Force, which ultimately contributed to the introduction of the helicopter into the SAAF. Major-General Robbs was at the time of the lecture - Director, General Planning, of the South African Defence Force – and current on Alouette IIIs. * “Nagana” - the Zulu word for the debilitating disease transmitted by the tsetse fly to domestic animals.

The most suitable aircraft available in the South African Air Force at that time for spraying was the trusty old Anson. The Avro Anson was a very useful animal, good for almost anything except the role for which it was designed, namely as a bomber, and for which role it was totally useless, due to it being absolutely vulnerable with a very limited payload. Having chosen the Anson, we started experimental work which was by adding two fuselage tanks, each of 90 gallons capacity holding a total of 180 gallons of DDT in liquid form, which was gravity fed to two venturi tubes at the rate of 5 gallons per minute on each side, giving the aircraft 18 minutes' spraying duration. A big snag was that when the liquid hit the airflow it was immediately rendered invisible, so a most laborious method had to be followed using flags on the ground, indicating a 17 yard swathe width, and with smoke signals for turning points. The flagged areas were sprayed a few times each, but; when the markers extended over hills or across undulating ground, you couldn't always see the intermediate flags, and it was a case of flying accurately on gyro. With the first run completed, the next lot of flags had to be charted out, and one can easily see what a frightful operation it all was. It was fine if there was a road along which you could dash in a vehicle to set up the next lane, but because of the terrain, it was a time-consuming and most laborious process.