PUBLISHED: 12:42, Mon, Sep 7, 2020 | UPDATED: 12:42, Mon, Sep 7, 2020
The locust warning comes after billions of desert locusts invaded East Africa earlier this year. Locust swarms of "biblical" proportions have also overrun parts of India, blotting out the skies over Gurgaon. Swarms of the winged pest can consume food for 2,500 people in a single day, making already vulnerable regions particularly susceptible to the threat.
Swarms can grow up to "several hundred square kilometres" with as many as 80 million adult insects per square kilometre.
On Friday, the United Nations Food and Agriculture Organization (FAO) warned of outbreaks in Botswana, Namibia, Zambia and Zimbabwe.
Although smaller than this year's plagues in East Africa, the UN said swift action is required to deal with the problem.
The migratory swarms threaten to exacerbate problems in areas struck by droughts last year as well as the economic fallout of COVID-19.
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Locust plague: Southern Africa is threatened by migratory swarms of locusts (Image: GETTY)
Locust plague: The ravenous insects threaten food insecurity in the region (Image: GETTY)
The UN's food agency said: "The situation is aggravated by the inaccessibility and ecological sensitivity of some of the affected areas."
One locust breeding ground has been identified in Botswana's Okavango Delta, a sprawling and lush plain that is flooded seasonally.
The Botswana outbreak, which began in May this year, was declared a regional emergency by June.
FAO southern Africa coordinator Patrice Talla said: "Some of the worst-affected areas are very difficult to reach."
At the start of September, the UN's Locust Watch group said swarms bred this spring still persist in the Horn of Africa.