The Horn of Africa has been hit by the worst invasion of flying desert locusts in 25 years, according to the U.N.’s Food and Agriculture Organization (F.A.O.). Swarms of massive flying bugs have threatened a region where 19 million people are already experiencing food insecurity. An unusual weather pattern that brought unseasonal rains has led to rampant reproduction of the insects. The locusts have devastated food and pasture in many regions not normally affected by locust invasions. The F.A.O estimates the increase in locust swarms will continue until June, warning it will take upwards of $70 million to contain the insects through widespread pesticide use across the region. “Under a worst-case scenario,” the invasion could become a plague if it is not contained quickly, the F.A.O. said in a statement.