The Very Hungry Caterpillar From Hell

There’s a new threat putting potentially tens of millions at risk in southern Africa. And it’s not war or disease, but caterpillars.

The fall armyworm, called such because it ‘marches’ its way through swaths of crops, was first discovered in Africa last year. (It’s originally from the Americas.) Since then, it’s wreaked havoc on staple maize crops in South Africa and Zimbabwe. There are reports the pest has also reached Zambia, Malawi, Namibia, Mozambique.

It could make an already untenable food situation even worse. Southern Africa is just beginning to recover from a scorching two-year drought that plunged seven countries to the brink of starvation.

“We have a situation where about 40 million people are food insecure until the next harvest in two months,” David Chimimba Phiri of the U.N. Food and Agriculture Organization told Foreign Policy. “If the armyworm is not controlled it could have devastating impacts on food security,” he said, speaking from FAO’s regional office in Zimbabwe.

Southern Africa is the new line of defense against an invasive species that the FAO warned could quickly spread to Asia and the Mediterranean, becoming “a major threat to agricultural trade worldwide” if left unchecked.

The FAO is convening a meeting with regional leaders to take stock of the new pest invasion next week. South Africa’s agricultural minister said his country is reacting “quickly” to confront the invasive species. Officials don’t yet know the full extent of the damage, though the Zambian government said the caterpillars already affected more than 10 percent of its crops.

Experts suspect the fall armyworm, native to North and South America, first slipped into Africa through food imports. Unwelcome, invasive species are a common side effect of global trade, a U.S. Department of Agriculture spokesperson told FP. In the United States, the USDA conducts overseas inspections of U.S-bound exports, monitors imports, and conducts state-by-state quarantines. Even then, some invasive pests like the Asian emerald ash borer or the gypsy moth slip through the cracks with devastating consequences for the states they land in.

Other countries, particularly developing ones in Africa, don’t have the same safeguards, making them even more vulnerable to invasive species. And the fall armyworm is a particularly nasty critter. Unlike other pests, it eats gains, seeds, flowers, wild plants, fruits, vegetables, anything it can get its mouth on, destroying crops it burrows into.

A trickle of armyworms can turn into, well, an army quickly: as dense as 1,100 caterpillars per square meter. Once it transforms into a moth, it can migrate hundreds of miles to new feeding grounds. And if African governments aren’t careful with pesticides, the armyworm could develop resistance to those, too, Phiri warned. A subspecies of the armyworm already became resistant to genetically modified crops in North America.

Phiri said the good news is governments took swift steps to identify infested areas and spread awareness of the pests to rural areas. And governments are urging farmers not to panic yet as they take stock of the new threat. Unfortunately for southern Africa, invasive species are nearly impossible to eradicate.

“It’s no longer a question of eradicating it,” Phiri said. “We have to find ways to manage it now that it’s here.”

Photo credit: Sam Droege/USGS Bee and Monitoring Lab/Flickr