Environmental, manpower and financial analysis of locust control in South Africa

[摘要] English: The brown locust, Locustana pardalina (Walker), has regularly recurring outbreaks inthe region Karoo region of South Africa. The endemic region comprises an area ofapproximately 40 million hectares. The locusts in the gregaria phase causeconsiderable damage to natural pastures and is in direct competition with stockfarming.The National Department of Agriculture administers locust control campaigns.Trained volunteers (supervisors and assistants) in the locust districts conduct locustcontrol campaigns and are remunerate for their efforts.Any sustainable agricultural setup and pest control should adhere to the followingthree criteria: environment, manpower and financial resources. This study was aimedat analyzing the 1996/97 locust control campaign, with the emphasis on the De Aar,Hanover, Hay and Postmasburg locust districts, based on these three criteria. Theproject was divided into two main parts: a component analysis for managerialpurposes and a spatial analysis (in ArcView-GIS) for operational purposes. Thecomponent analysis was done on supervisor level within the districts and the spatialanalysis was done on both farm and district levels.Great variation existed between the supervisors and districts analysed in all threecriteria. The highest number of bands and swarms was controlled in the Hanoverdistrict (5392), followed by Hay (1 961) De Aar (1 519) and Postmasburg (859).The supervisors in the De Aar district controlled a higher percentage of hopper versusadult locusts (87 vs. 13 %). The opposite was encountered in Hanover (28 vs. 72 %),Hay (32 vs. 68 %) and Postmasburg (45 vs. 55 %). The highest total area (Ha) bandsand swarms was sprayed in the De Aar district (Il 410), followed by Hanover (9493), Hay (5 054) and Postmasburg (2 816). Locusts had the highest impact ongrazing in the Hanover district.Effective control operations resulted in small areas of each district being sprayed: DeAar (2,13 %), Hanover (2,63 %), Hay (0,40 %) and Postmasburg (0,16 %). An earlywarning system to facilitate locust control is possible with the incorporation ofreliable biotic and abiotic data.Dissimilarities in manpower utilisation were evident through the area (Ha) andamount of pesticide sprayed per assistant per day in the various districts.The highest numbers of supervisor (800) and assistant (2 039) days were recorded inthe Hanover district and the lowest numbers (172 vs. 129) were recorded in thePostmasburg district. A geographic information system enables visual monitoring ofjob creation and socio-economic implications of locust control.The pesticide and travelling expenditure accounted for most of the expenses. Theexpenses per hectare (RlHa) were the highest in the Hay district (70,07) and thelowest in Postmasburg (23,17). The actual financial damage caused by the locustswas much lower than the potential financial loss. Investment return factors (IRF's) ofmore than one hundred were achieved in all the districts.The integrated operational and management information system enables visual accessto extensive locust control data. This information system eases management byfacilitating proper planning within and among campaigns.

[发布机构] University of the Free State