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 than its neighbors to combat the pest. 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.
Annual outbreaks of African armyworms have become the norm in much of sub-Saharan Africa. So far in 2017, ongoing infestations of the caterpillar have been reported in Malawi and Zimbabwe. Its effect on crops varies, but a 2012 outbreak led to an 11 percent loss in Zambian corn production.
By comparison, the fall armyworm — just one of at least 30 other armyworm species — has been known to destroy up to 73 percent of crops in previous outbreaks in the Western Hemisphere. The pest made its first appearance in Africa last year, and it has since been reported in South Africa, Zimbabwe, Zambia, Malawi, Namibia, Ghana and Mozambique. In each of these countries, agriculture has already been suffering from severe drought related to the El Nino weather pattern over the past couple years. Extended drought also makes crops more susceptible to
Thus, the emergence of a new pest has the potential to devastate crop production at a time when the threat to food security in the region is already high. The drought is estimated to have reduced the region’s food availability by 15 percent, with a shortfall of 9 million metric tons in cereals alone. When the most recent El Nino gave way to neutral and then La Nina conditions, hopes had been high that the current growing season would help replenish food stocks.
An unimpeded recovery no longer appears likely. Estimates vary, but roughly 130,000 hectares (about 321,000 acres) of Zambian crops have been affected thus far. In Zimbabwe, the pest has been detected in all 10 of its provinces. Some 2,000 hectares of crops have reportedly been destroyed in Malawi.
Pesticides and pheromone traps are the most common methods used to control both the African and fall armyworms. The African armyworm is easier to contain than its cousin, in part because its hatches typically occur only six times per year (compared to 10-12 times for the fall armyworm). But combating the fall armyworm is actually fairly easy for better-funded commercial farmers, so long as they have access to the necessary tools and technologies. Individual and subsistence farmers will have more difficulty bringing the pest under control.
South Africa is already making strides toward controlling the caterpillar by prioritizing the approval of two new pesticides. The use of genetically modified maize in South Africa will also help limit the outbreak. Monitoring the problem, educating farmers and spreading technical information will also be key to any effective effort to fight the pests. But each of these steps requires substantial sums of money and sectorwide coordination to be effective, meaning many subsistence farmers will remain more vulnerable than their commercial counterparts.
This makes the risks of the outbreak bigger in poorer sub-Saharan countries such as Zambia and Zimbabwe — two countries already facing dire financial challenges. Zambia has spent $3 million in an attempt to control the pest, but roughly three quarters of its farming activities are small-scale subsistence operations. In Zimbabwe, where the agricultural sector employs most of the population, many people rely on subsistence farming for their own food supply. Threats to such supplies are cause for humanitarian concern.