In Africa, swarms of desert locusts are threatening crops from the Atlantic to the Red Sea, and 12 million hectares of often fragile environments have been treated with insecticides. This is worrying, as the last major swarms in 1988 took several years, 1.5 million litres of chemical pesticides and US$300 million to bring under control. Since then, ecologists, economists and politicians concerned about the effects of these pesticides on human health and the environment have agreed that alternative methods were needed to combat locust outbreaks — ideally before the locusts invade agricultural land in the Sahel region.
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