The locust has always been a feared insect of farmers because of the devastating effect they cause on crops and farms.

Normally locusts live alone and will cause no problems at all. In certain conditions though the locusts can form an enormous destructive swarm.

If the locust nymphs develop in uncrowded conditions where they have plenty of food for themselves and lots of space they are said to be in the solitary phase.

However, if they develop in a crowded area, they are said to be in a gregarious phase. It is this phase that causes a swarm of migratory locusts.

Migratory means that the locusts will move from one area to another looking and eating all the vegetation they can find. Once they have devoured one area they search for some more plants to eat.

A swarm of locusts may extend over hundreds to kilometres. It will eat thousands of tonnes of vegetation and grain in a day. Nothing green is left uneaten by the swarm.

Animals and people will face starvation as their pastures and crops are devastated.