The U.N. Food and Agriculture Organization (FAO) said the infestation emerged as a new breeding season began at the end of August.

A second wave of reproductions bolstered the number of insects at the end of October.

“The infestation is huge,” Abdallahi Ould Babah, head of the center for controlling the desert locust in Mauritania, told Agence France-Presse.

He said that teams of locust fighters have been able to treat only about 16 square miles with pesticides so far. The region is remote and hard to reach because of its vast sand dunes.

FAO specialists say the current infestations consist mainly of wingless hoppers, which will mature and move into other areas.

One area of most concern is in Western Sahara, where vegetation is green from unusually heavy rainfall during September.

The agency cautioned that if temperatures remain warm and are accompanied by additional rain, the adults are likely to lay eggs in areas of green vegetation late in December and during January.

Photo: Food and Agriculture Organization