Jim McMahon/Mapman®

Swarms of locusts dense enough to block out the sun are quickly cutting a path of destruction across Kenya and other countries in East Africa.

Unusually wet weather has caused billions of the grasshopper-like insects—which reproduce in moist conditions—to spread across Ethiopia, Somalia, South Sudan, Uganda, and other countries. It’s the worst locust outbreak that parts of East Africa have seen in 70 years.

The insects pose a serious threat to people in that region. The swarms contain as many as 200 million insects per square mile—and they devour crops and destroy farmland at an alarming rate. In a single day, an average swarm can travel more than 80 miles and destroy enough food to feed 35,000 people.

That’s especially problematic for countries like Kenya, where millions of people already face serious food shortages due to poverty and local conflicts. Experts with the United Nations (U.N.) Food and Agriculture Organization say the locust outbreak—if left unchecked—could cause an additional 20 million people in the region to go hungry.

To address the growing crisis, U.N. officials are asking the international community for about $75 million in aid to spray pesticides from planes—the only effective method for combating the locusts. 

If nothing is done, they warn, the swarms could grow 500 times larger by June.

“The magnitude of the problem is just so big,” says Cyril Ferrand, a U.N. official in East Africa. “The locusts are a moving target, and we are racing against time.”