After desert locusts invaded her farm in central Kenya, Mary Muthoni, 61, ran around her corn fields shouting and banging on an old iron sheet in a desperate attempt to drive them away.

¡°They came here yesterday evening and sat on top of these trees as though to rest there for the night,¡± said the mother of seven, who lives in Mahiga-Meru village in Laikipia County.

¡°This morning, they decided to come down on my maize farm and started eating it, destroying the maize in the cobs and also the leaves,¡± she said last month.