A Century of Locust Control in South Africa

Literature › Works

R. E. Price; H. D. Brown (2000). A Century of Locust Control in South Africa. Workshop on Research Priorities for Migrant Pests of Agriculture in Southern Africa, Plant Protection Research Institute, Pretoria, 24–26 March 1999 (eds R. A. Cheke, L. J. Rosenberg and M. E. Kieser). Natural Resources Institute, Chatham, UK.

Type	conference paper
Scope	Comparative and methods
Method	synthesis review
Period studied	1906–1999
Regions	South Africa, Karoo, Northern Cape, Orange Free State, Namibia, Botswana, SADC region
Themes	agriculture land, methods data sources
Citation key	price2000

Argument

An entomological and institutional history of chemical locust control in South Africa, focusing on the Brown Locust endemic to the Karoo. The authors argue that state-led control at source, run by the Department of Agriculture with legally mandated farmer reporting and a temporary 'commando system' of farmers and labourers, has prevented regional plagues for 50 years. Still, outbreaks recur almost every year and have been more intense since the mid-1980s. Control may even perpetuate outbreaks by stopping populations from fully gregarising and burning out. Falling survey budgets, the decline of regional collaboration and a depressed farm sector, with absentee farmers, are eroding capacity. They review technical and strategic options, including baits, barriers, targeting adults only, biopesticides and IPM, without reaching a firm conclusion on cost-effectiveness.

Evidence and method

Departmental and PPRI operational records; a district-level series of the number of magisterial districts in South Africa, Botswana and Namibia where locusts were chemically controlled each year, 1947–97 (Figure 2); unpublished annual situation maps from 1984; insecticide trial records; campaign cost figures for 1985–86 and 1995–96; and the published entomological literature (Smit, Lea, Faure, Matthée).

Findings

• Chemical locust control in South Africa dates from about 1906, beginning with sodium arsenite applied in Natal. (p. 1)

  It is just over 100 years since the chemical control of locusts began in South Africa when sodium arsenite dust was first applied by hand to Red Locust hopper bands

• The 1985–86 Brown Locust upsurge was massive in scale. (p. 2)

  over 250,000 hopper bands and 40,000 fledging adult swarms were controlled in the massive 1985–86 upsurge

• Containing swarms in the Karoo has prevented crop damage elsewhere and averted regional food-security threats for 50 years. (p. 3)

  Virtually no crop damage outside the Karoo has been reported and the threat to food security within the SADC region has been averted.

• Outbreaks are near-annual: only 5 of the past 50 years saw no chemical control, measured by infested magisterial districts. (p. 4)

  there have only been 5 years in the past 50 when no chemical control was undertaken

• Control is a state responsibility, with legal reporting obligations on farmers. (p. 4)

  Farmers are legally required to report the presence of locusts on their land and locust control is the responsibility of the National Department of Agriculture.

• Forecasting capacity built from the 1940s to the mid-1960s has deteriorated through budget cuts. (p. 6)

  However, financial cutbacks have severely reduced the ability to undertake such comprehensive surveys and our ability to forecast outbreaks has deteriorated.

• BHC, used 1945–86, persisted in the Karoo and accumulated in humans, leading to its phase-out. (p. 6)

  the organochlorine BHC was found to persist unduly in the Karoo environment and to have accumulated in the human population

• Farm-sector distress is undermining the commando-based control system. (p. 8)

  the depressed farming situation has resulted in an increased number of absentee farmers and locked farm gates

• Outbreaks have intensified over the last 15 years despite modern insecticides. (p. 8)

  suggests that more intense outbreaks occurred during the past 15 years than occurred previously, despite the extensive use of modern insecticides.

• Campaign costs to the taxpayer were substantial. (p. 8)

  The massive outbreak in 1985–86 cost over R50 million to control (equivalent to US$25 million at the time), while the recent outbreak in 1995–96 cost approximately R14 million (US$3.5 million).

• Abandoning control in favour of direct crop protection is politically unlikely because of regional food-security sensitivities. (p. 10)

  it is unlikely that this strategy will be adopted in southern Africa due to the national responsibilities regarding migrant pest control and the political sensitivity regarding food security within the region