A swarm of desert locusts following a poor harvest season has added to fears about a lack of food for millions in Kenya, as the country grapples with the effects of COVID-19.

The desert locusts—in the worst invasion in Kenya in 70 years, according to the United Nations—have destroyed huge swaths of crops and pasture in the region, said farmer Joyce Mutinda, but the extent of the damage cannot yet be determined since new swarms are spreading.

Swarms of desert locusts can stay in the air for very long periods, traveling up 130 kilometers, or 80 miles, each day, according to the Food and Agriculture Organization of the United Nations, and the swarms can vary in size, covering from 1 square kilometer to several hundred square kilometers, with up to 80 million adult locusts in each square kilometer.

“There is no maize,” said Regina Kasyoka, a 36-year-old farmer from the food basket region who did not harvest enough crops compared with past seasons.

In the eastern food basket region, the crops play a vital role in cushioning the country’s food shortage.