Desert locust swarms are set to invade North Africa in the coming weeks, the United Nations Food and Agriculture Organization (FAO) warned today, as it highlighted ongoing efforts to raise almost $6 million still needed to cover regional control costs for the rest of the year.

"Prevailing winds and historical precedents make it likely the swarms, once formed, will fly to Algeria, Libya, southern Morocco and north-western Mauritania," said an FAO Senior Locust Forecasting Officer, Keith Cressman, in a press release. "Once there, they could damage pastures and subsistence rain-fed crops. They could also pose a threat to harvests in Chad, Mali and Niger."

This year marks a 250-fold increase in locust populations after "good" summer rains offered favourable conditions for two generations to breed in West African's Sahel region, FAO noted in a press release. Swarms, which can contain tens of millions of locusts, are currently forming in Chad, and are poised to form in Mali and Niger.

FAO said it has urged Algeria, Libya, Mauritania and Morocco to be prepared to mobilize their field teams to detect the arrival of the swarms and control them.

Swarms can fly up to 150 kilometres a day with wind, while a single desert locust adult can daily consume roughly its own weight of about two grams in fresh food. Even a very small swarm can devour enough crops in a day to feed about 35,000 people, according to FAO.

Conflict in Mali has restricted FAO's ability to monitor the locust threat there, with Mr. Cressman noting that security challenges and difficult access to some locust breeding grounds meant it was unlikely all locust infestations would be found and treated.

FAO added that ground teams began spraying in Chad in early October, while military escorts are assuring the safety of spray teams beginning their work in Niger.

The UN food agency said donor countries had met $4.1 million of a $10 million appeal to maintain and expand operations, and that efforts were currently underway "to obtain the remaining funds."

Support from the governments of France, United Kingdom and United States, as well as bilateral assistance to Niger, had enabled field operations to continue throughout the summer in Mali, Niger and Chad, FAO noted.

It added that a regional meeting organized last month by the FAO Commission for Controlling the Desert Locust in the Western Region and the World Bank confirmed that the full appeal is sufficient to cover the costs of the control campaign in the region until December.