A tree stripped of most of its leaves by a locust swarm Swarms can travel up to 60 miles a day, and I can remember them looking like clouds of smoke, swirling and pluming upwards on a vast scale.

Chinese factories are producing thousands of tonnes of a "green zombie fungus" to help fight the swarms of locusts plaguing east Africa. Metarhizium is a genus of fungi with nearly 50 species ...