Alien Armyworms Invade Corn in Drought-Hit Southern Africa

After southern Africa’s worst drought in more than 35 years ravaged crops and sent food prices soaring, farmers are battling a new crisis: alien armyworms.

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The fall armyworm that’s native to the Americas has arrived in southern Africa for the first time, wiping out tens of thousands of acres of corn fields. For a region trying to recover from drought, the pest brings renewed fears of food shortages and inflation. The United Nations’ Food and Agriculture Organization says the effects could be devastating for the area if its spread isn’t controlled.

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How did the pest arrive in Africa? The answer isn’t yet clear, though [Georg Goergen, an entomologist who’s studied their arrival and migration on the continent at the International Institute of Tropical Agriculture in Ibadan] says there is evidence that there were at least two separate introductions. One of the theories he’s investigating is that the moths flew over the Atlantic ocean. That would mean a journey of at least 3,000 kilometers between the closest points of South America and Africa.

“Among the speculations, climate change-induced variations in high-altitude wind streams may have favored the shift from one continent to another,” he said in reply to e-mailed questions.