Addressing the locust crisis in East Africa: A Q&A with Dr. Christina Owen

Part of the problem with locust swarms is they can be hard to track, particularly if they first arise in an area with very few people—as these did—or surveillance is hampered, due to COVID-19, political instability in Yemen, or just a lack of resources. We know this is already the worst invasion Kenya has seen in 70 years, and the worst in Somalia and Ethiopia in at least 20. Large swaths of these nations are being impacted by swarms, as well as parts of Eritrea, Eastern Uganda, South Sudan, and Djibouti. And that’s just in Africa. The Arabian Peninsula is also affected, particularly Yemen and Oman, as well as Pakistan and Iran.

The lifecycle of a locust is more dependent on the weather than the season. Desert locusts live in sandy areas and feed on vegetation. When it rains, locusts lay eggs in damp sandy soil. When these eggs hatch, small grasshopper-y type insects called “hoppers” emerge. The hoppers eat the surrounding vegetation—and when there has been a lot of rain, there is lots of vegetation to eat. As this food source runs out, much larger populations of hoppers become compressed into smaller feeding zones.

Once a high-density of hoppers are packed together like this, one of the most bizarre features of desert locusts emerges. As their hind legs bump into each other, it triggers a physiological and hormonal response. The locusts go from being solitary little green grasshoppers to what is called their “gregarious type.” Their color changes and they start to behave as a swarm. They also become extremely voracious, eating everything in sight. A one-square-kilometer-sized locust swarm can quickly destroy enough crops to feed 35,000 people for a year. And when there is no vegetation left, they fly somewhere else en masse.

This cycle can continue as long as there is moist, sandy soil to breed in and vegetation to eat. Sadly, this is where you can see a clear connection between atypical weather patterns arising from climate change and the locust crisis. The locusts we are seeing now are the descendants of a population explosion that started in 2018-19. In Ethiopia, the hope was that drier weather would mean less moisture in the soil and thus fewer locusts. But instead the region, along with the Arabian Peninsula has experienced abnormal monsoons and cyclones. Huge storms meant more damp soil, more vegetation, and more locusts. That really set us off on a bad path.

And it sounds like it is getting worse. In May, the FAO said this already sizable locust population could expand by 400 to 500% by the end of this month. Is that happening?

I think the jury's still out. Right now, in Kenya and Ethiopia, most of the locusts are still hoppers. While hoppers are easier to eradicate, surveillance efforts are also a lot harder before they are airborne. We will know in the next week how successful trackers were at detecting and spraying the largest hopper populations. If they found these hopper bands and managed to kill them before they take flight, then we should see fewer swarms and a lower population soon.

But if we missed a lot, then in the next two-three weeks, we could see a tremendous increase in these already massive swarms. These swarms will then move again, further into Ethiopia, into South Sudan, and potentially across the Sahel.

One direct impact of the coronavirus has been simple procurement. We have seen real challenges with supply chains in terms of getting insecticides, spraying equipment, and airplanes to the affected countries. For example, Kenya could not get the helicopters they needed because of the sheer number of quarantines involved to get them there. Pesticide shortages have been common as well.

Another issue is restrictions on movement. Some country survey teams have been able to get exemptions from local governments to allow them to continue looking for locusts. But not every place has been ok with that, and just getting the waivers in place has taken up precious time.

Plus, just in general, African countries are facing resource constraints, both because of the sheer magnitude of these swarms and the convergence of crises at the same time. Kenya has been experiencing significant floods as well, and resources to deal with all of these are running low.

Definitely. We are looking at the possibility of a serious humanitarian disaster that needs global attention. A recent report by the International Rescue Committee suggested this crisis could affect a full tenth of the world’s population and plunge nearly five million people in East Africa into famine. Along with the sheer loss of sustenance, these swarms will have a terrible impact on people’s livelihoods—especially for smallholder farmers. Families who after years of work have managed to rise just above the poverty line will fall back.

The tragedy is locusts are just not a problem that an individual farmer can solve, especially at this scale. We are talking about swarms that are the size of major American cities. Locust outbreaks require a coordinated regional or national response with airplane support, and local farmers just do not have that.

We are seeing some promising technologies that leverage crowdsourcing, mobile apps, and artificial intelligence to help with surveillance and eradication efforts. For example, mobile surveillance apps are being used to get more local locust reports that in turn help direct where airplanes can spray.

Another innovation is using a more epidemiological approach to locusts—applying models and algorithms to try to predict both their spread and the optimal control strategy. Do we have to spray everywhere, or are there certain places we can focus on and still achieve the same level of control, while managing our resources better?

FAO is also collaborating with partners like NASA and Penn State to improve remote sensing and weather information. If we know where the locusts and crops are, we can figure out high-risk areas for both hopper bands and eventual swarm migration. And if we cross-reference this information with soil mapping, which is something the Gates Foundation has invested in, we can figure out the Venn diagram where the right kind of soil and moisture overlap. Then we can figure out where the hot spots are.

I know most of us are experiencing crisis overload, but this catastrophe is happening right now. These locust populations are potentially expanding across the region, and the swarms are not going to simply stop growing because the money ran out to address them, or because we were focused on COVID-19.

The faster we respond, the better chance we have of containing ever bigger and deadlier swarms. So, it is critically important to contribute now to keep the pressure on.