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Science et changements planétaires / Sécheresse. Volume 7, Number 2, 109-13, Juin 1996, Étude de cas

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Author(s) : Alexandre Latchininsky, Fourkat A. Gapparov

Summary : The delta of the Amudarya river situated to the south-east of the Aral sea was one of the most important permanent breeding centre of the Asiatic Migratory locust, Locusta migratoria migratoria (Linné, 1758) in the former Soviet Union. The area of reeds that could be colonized by this locust is as high as 14 thousand km 2. In the outbreak years, it is necessary to control the Migratory locust on 500,000 ha. The second species of economical importance, the Italian locust Calliptamus italicus (Linné, 1758) was restricted only to the irrigated zone. It colonized the sites of the anthropogenous origin (road-sides, fallows, uncultivated lands with weeds, etc.). The drying of the delta after the excessive uptake of water from Amudarya for irrigation has led to the radical changes in the environment and, consequently, in the locust situation. The delta was subject to the rapid desertification. The area of the humid biotopes (reeds) has fallen dramatically. The river forests are at the limit of disappearance. The mesophilous acridian species are replaced by the species of the semi-desert fauna. The sites favourable for Locusta m. migratoria are reduced, its economical importance became of the second level. On the contrary, the environment became most favorable for C. italicus which, due to its ecological tolerance and high polyphagy, colonizes readily the vast surfaces menacing the cash crops (cotton). To protect them, several annual chemical treatments are necessary on hundreds of thousands of hectares that rises the risk of environmental pollution in the conditions of ecological catastrophe.

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