Keith Cressman is senior locust forecaster at the U.N. Food and Agriculture Organization.
Insects wipe out crops and pastures, damaging food supply and livelihoods

A man attempts to fend-off a swarm of desert locusts in Kenya on Feb. 21: it is the worst outbreak to strike the country in 70 years. © Reuters
Keith Cressman is senior locust forecaster at the U.N. Food and Agriculture Organization.