A major outbreak of an invasive caterpillar in parts of sub-Saharan Africa has sparked widespread worries about food security. The pest, a species endemic in the Americas known as the fall armyworm, is more difficult to eradicate than its local cousin, and its effect on the region's crop production -- and its food supplies -- will be magnified by the lingering effects of recent droughts. The repercussions of the infestation on countries in the region will vary: As the region's largest producer of corn, a main armyworm target, South Africa has the largest vulnerability, but it is better equipped to combat the pest than is its neighbors. Meanwhile, countries such as Zimbabwe and Zambia, which lack money or experience to deal with the fall armyworm, face substantially higher risks, particularly among subsistence farmers....
