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Africa imports more than $500 million worth of pesticides. In the last 10 years, locust and grasshopper control programs have cost between $ 7 and 40 million, or between 1 to 9% of total pesticide spending. Total donor support for locust control reached $ 275 million for the outbreak of 1986-1989, 36% of which for pesticides. Deset Locust, Red Locust and migratory locust control in FAO’s EMPRES central region, Mozambique and Madagascar are heavily donor financed, and donors are the key decision makers. Lately, the cost efficiency of locust campaigns have been put into question (Joffe 1995), and concern about environmental costs are increasing (OTA, 1990). Therefore, a 20% substition of Metarhizium for chemical acridicides seems possible.
The market for acridicides used against Sahelian grasshoppers is equally complex. Relatively good data are available for Niger, a country almost completely located within the Sahel. It has around 10 million ha under cultivation, 6 m of which in sorghum and millet (Service de l'Analyse des Politiques et de la Coordination des Statistiques. 1996.). Over the last 20 years, there have been regular treatments against locusts and grasshoppers, ranging from 0.2 to 1 m ha (not all land under cultivation, and not all infested land), and 0.7 m ha on average from 1987-90 (Landry, 1992).
Assuming that 60% of the area infested was treated, we can calculate an average infestation rate of 15% of sorghum millet area for a typical Sahelian country. Extrapolation would give a (very) rough estimate of an infested area of 2 million ha in the Sahel, 3 m ha for West-Africa.
Although no systematic data base exists, Monard (1994) collected the available data from the OCLALAV countries. The average hectares treated (mostly but not uniquely against grasshoppers and locust) for (mostly) 1986-1991 for 8 countries in West Africa total up to 2.5 m ha. This is in the same range as the first estimate.
A market for acridicides against grasshoppers in the humid areas of West Africa is also emerging. In Cote d’Ivoire for example, the variegated grasshopper is a major problem of coffee and cassave, minor of cotton, banana and vegetables. Estimates of the total market of acridicides in this country between 10,000 and 200,000 ha. Given the size of other areas with similar climate, a regional market of 50,000 to 1 million ha seems realistic.
Some other commercially interesting situations include Tree Locust in Gum Arabic plantations, Brown Locusts in South Africa, and Zonocerus elegans in Kenya. A survey of the national plant protection agencies is being prepared on past and current pesticide use and policy.
Worldwide, after some 30 years of research, interest in biological pesticides is slowly increasing. A full discussion paper analyzing this slow uptake is in preparation.
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