Part of a swarm that measured 14x10 km flying westwards in northern Mali. This was part of the westward migration at the end of the monsoon breeding in the Sahel. - - Desert Locust Campaign. 1988 was a year of a major upsurge of the plague of the desert locust (Schistocerca gregaria) on a scale unknown since the mid-fifties. Swarms escaping from the spring breeding grounds in northern Africa, crossed the Sahara on a wide front to invade all the Sahelian countries from Mauritania and Senegal, to Chad and the Sudan. From July onwards, locusts matured and bred, giving rise to numerous hopper bands and new generation swarms. Control operations, coordinated by the Emergency Centre for Locust Operations of the Food and Agriculture Organization of the United Nations (FAO), were often spectacular but were not able to prevent all escapes. Newly formed swarms emigrated from the sahel, some back to the winter-spring breeding grounds in North-west Africa, but many were carried by winds to the Atlantic ocean. Most were drowned, but some reached the Caribbean islands, for the first time in recorded history.