The International Red Locust Control Service (IRLCS) was formally established in 1949 with the primary objective of controlling locusts in their outbreak areas, thereby preventing the recurrence of plagues. The name of IRLCS was subsequently changed in 1970 to the International Red Locust Control Organisation for Central and Southern Africa (IRLCO-CSA), but retained the same objectives. Over the years, IRLCO-CSA has experienced changes in membership and locations of its Headquarters and operational centres. Its principle mandate has remained the same even though it has been modified and rationalised from time to time. The organisation carried out investigations that led to the identification of the red locust outbreak areas and the development of various control technologies. Control methods developed from the original physical ones which were laborious and inefficient; to insecticide dusting and baiting; to the spraying by aircraft. In its history of locust control programmes, IRLCO-CSA has used arsenic compounds, BHC, DNOC, dieldrin and fenitrothion as insecticides. The success that IRLCO-CSA has enjoyed in its 50 years history has been thanks to the cooperation of countries in eastern, central and southern Africa which are vulnerable to attack by the red locust, and the international community.

In 1996, many swarms of red locust, Nomadacris septemfasciata (Serville), formed in the Buzi-Gorongosa outbreak area in Mozambique. Some of these swarms migrated and crossed international boundaries, on a scale not seen since the last plague of 1929–1944.

The swarms did not breed in countries that they invaded, namely, Zimbabwe, Zambia, Botswana and South Africa. On the other hand, in Malawi, successful breeding by the swarms resulted in hopper bands. Filial generation outbreaks continued into 1997 in the breeding area, but at a reduced scale.

An analysis is made of the possible causes of the upsurges of 1996 and the likely implications to the preventive control strategy that has been the principle for red locust plague prevention.

There is need for a further comprehensive study of the Buzi-Gorongosa plains so as to understand better the factors that contribute to its high potential as an outbreak area.

This paper gives an account of the activities of the International Red Locust Control Organisation for Central and Southern Africa (IRLCO-CSA) in the management of the red locust, other locust species and non-locust migratory pests in the 1980s and 1990s. It also analyses the advances made by IRLCO-CSA in implementing a preventive control strategy so as to avoid future plagues and outlines the activities of IRLCO-CSA during periods of locust recession.

There were widespread upsurges throughout the 1980s into the 1990s, with outbreaks being recorded throughout the period 1985–1997. Without doubt, the period 1981 to the present, was the most active since the suppression of the last plague in the 1940s. It is concluded that the threat of red locust plagues is not yet over and that the continued existence of IRLCO-CSA remains key to the food security needs of the region.

The red locust, Nomadacris septemfasciata (Serville) is one of the major plague locust species of serious potential threat to agriculture in Zambia. Two of its eight outbreak areas, Mweru wa Ntipa plains and the Kafue Flats, are found in Zambia. The Kafue Flats have now become more important because of high levels of locust activity, occasionally forming swarms. Locust control in Zambia has been mandated to the International Red Locust Control Organisation for Central and Southern Africa (IRLCO-CSA), a regional cooperative effort of 8 member countries. Regional cooperation for locust control has proved practical and economical for Zambia.