just asking questions

So There’s a Locust Plague Too?

A volunteer sprays pesticide in eastern Kenya — which is suffering from its worst locust outbreak in 70 years. Photo: Tony Karumba/AFP via Getty Images

It’d be easy to quip biblically about the simultaneous breakout of pandemic and plague if not for the vast human toll that the intercontinental crises are exacting. As the coronavirus continues to spread on six continents, a desert locust outbreak has inundated East Africa with hundreds of billions of bugs, causing food shortages in Kenya, Somalia, and Ethiopia. “It was like an umbrella had covered the sky,” Joseph Katone Leparole, a 68-year-old living in central Kenya, told the New York Times.

In our age of overlapping crises, it shouldn’t be a surprise that climate change can be identified as a factor in the upsurge, the technical term used for such a natural disaster that is just below plague. It began in 2018, when a pair of cyclones came in from the Indian Ocean and hit the “empty quarter” of the Arabian peninsula — the vast desert region near the borders of Saudi Arabia, Yemen, and Oman. In a speech before the African Union in February, U.N. general secretary António Guterres explained the unfortunate cycle: “Warmer seas mean more cyclones, generating the perfect breeding ground for locusts.”

“When you have rains associated with cyclones, they’re much stronger than normal,” said Keith Cressman, the senior locust-forecasting officer at the United Nations’ Food and Agriculture Organization. “When those rains fall in desert areas with sandy soil, that will flood the soil. Once those floods recede, the soil retains so much moisture that it allows desert locust females to lay their eggs probably for a period of around six months.”

From these ideal conditions, the bugs moved south into Yemen (already in a food crisis, Yemenis turned to them as a protein source) and into the Horn of Africa. The spread was rapid: A single locust can travel up to 90 miles in a day and eat its own weight in plant matter, of which there was a bounty, thanks to the excessive rains. They also turned north, across the Persian Gulf into Iran, and into India and Pakistan last summer. National emergencies have been declared in Pakistan, Jordan, and Somalia to help mobilize a response: The only effective control operation once a swarm is in motion is to spray pesticide directly on the bugs from the air.

To help understand the crisis, Intelligencer spoke with the FAO’s Cressman about some of the bugs’ idiosyncrasies and what to expect in the coming months.

The FAO projects that the number of locusts could grow 400 times by June if not treated. Could you break that down?

The life cycle of a locust is about three months, so after three months the adults are ready to lay eggs again. With each three-month generation, there’s a 20-fold increase in locust numbers. Locust females lay around 300 or more eggs — more than 90 percent of them die or the resulting hoppers don’t make it to adulthood. Out of all that breeding, for every single female locust there’s about 20 locusts in the new generation that make it. It’s an exponential increase, so after three months you have 20 times, after six months you have 20 squared, so that’s 400 times. After nine months, you’d have 20 cubed, which is 8,000 times. When you get that type of exponential breeding, then those locust numbers rapidly increase, and that’s how swarms form, basically.

So with these new generations, countries in East Africa that have already been inundated could face even more locusts?

Absolutely. There’s a generation in progress now and breeding in Ethiopia, Somalia, and in Kenya. Conditions will probably remain favorable there because of a cyclone in northeastern Somalia in December. Conditions are probably favorable in those three countries until June, so that will allow another generation to occur before then.

How are the outbreaks in Pakistan, Iran, and China connected to those in East Africa?

For China, it’s a completely different species — apples and oranges. But the one in Iran and Pakistan, yes. What’s going on now in Pakistan is old swarms leftover from last summer that have been slowly maturing and now they’re ready to lay eggs, not in the deserts on the border of India and Pakistan but in the desert closer to Iran and Afghanistan.

There’s an FAO map that shows them traveling directionally from the horn of Africa over Arabian sea. Can they travel over water?

No problem. In the late ’80s, they went from West Africa to the Caribbean. They crossed the Atlantic in about ten days.

Photo: United Nations

How does that work if there’s no food?

They eat a lot before or after! The way it worked crossing the Atlantic was, they had enough fuel in the tanks but still needed to rest sometimes, so they’d rest onboard ships, and then they’d take off again. If there weren’t any ships, they’d land on the surface of the ocean, and then a second swarm would come and land on top of the first swarm and rest, and the second swarm would take off and continue flying and the first swarm would drown.

My impression was that they choose to go where food is. Do they have choice as a unit where they’re going or is it randomized by wind?

They seem to decide whether they want to take off or fly with the prevailing wind or not, in which case they’ll sit on the ground. They can somehow sense winds when they come from different directions, but they can’t fly like birds against the wind. So they are a victim of the wind, but still they do control motion to an extent.

Without human intervention, how does a locust outbreak end?

There would have to be a failure of the seasonal rains — that’s usually how mother nature helps to bring these things under control. Sometimes the winds will push locusts into areas they just don’t want to be in. For instance, if they got pushed further into the Democratic Republic of the Congo or into cold areas where they would die, or areas that are very tropical where they would pick up a lot of pathogens and die. They’re very susceptible to funguses. Like those guys that got pushed across the Atlantic ocean in the ’80s, they died immediately when they landed.

What happens in a country like Iran where there’s a simultaneous outbreak of locusts and the coronavirus.

Fortunately, different parts of the government are responding, so the Ministry of Agriculture is dealing with locusts and the Ministry of Health has to deal with the coronavirus. The resources and manpower are in completely different sectors of the economy. But any additional challenges that a country faces, they can have impacts on the control operations, and they might not be as effective as hoped.

What about states in open conflict or with major security issues, like Yemen or Somalia?

Yemen is very critical because it’s a frontline country for desert locusts. Desert locusts are there every year, and there’s a number of different breeding areas along the coast in the wintertime in the interior. It’s a country that has a really spectacular habitat for desert locusts, and when it rains, those locusts take advantage of it.

That’s probably one of the reasons why the locust infestation shifted from the empty corridor in 2019 across to the Horn of Africa in the summer, because they stopped off in Yemen for a generation of breeding in the spring. Because of the conflict, there’s very little that can be done. It’s just not safe for the national locust teams to to operate throughout the country to undertake the survey for control operations. There are a few limited areas they can work in, but it simply isn’t enough.

Fortunately, in Somalia, the key locust breeding areas are in the north of the country, which is a region that’s much easier to operate in. It’s much safer, so national teams can get in there and do the survey and control operations. However, in the south and central parts of the country, it is much more challenging. Those parts of the country don’t see locusts often, maybe once every few decades, so they also have very little capacity.

What about in South Sudan, where there is already a food shortage?

The good news is, it’s not really their typical habitat. It’s not dry enough, and they don’t have so much sandy soil. It’s more of a clay soil, and there’s much more vegetation cover, so this makes it hard for the females to find bare, empty places to lay their eggs. And we’ve seen this with those locusts that got into northeastern Uganda and the southeast of South Sudan: They flew around, and the females became so desperate that they just kind of dropped their eggs on top of the soil, which means that they immediately dry out and die. Desert locusts don’t do this very often. These guys are masters of survival. They’re professionals, so this means that those females are really desperate. So probably South Sudan is much more of a transit zone. Later on in the spring, a new generation of swarms will likely form in northern Kenya. Once it drys out there, they will be moving back into Somalia, back into Ethiopia, and probably into north Sudan to get really into the Sahara and the deserts they prefer.

What’s the most effective form of prevention and treatment if an outbreak is already in motion?

When you have these cyclones, it comes back to climate change: We’re starting to see more patterns of severe weather, which means unusually heavy rainfall, cyclones,t hese things. You can’t prevent them really. So we’re going to have to develop better mechanisms to respond to them better. Basically it means that countries are going to have to be very well prepared. To visit a wildfire metaphor, you need to have a lot of good fire stations with well trained crews and fire trucks — it’s the same with desert locusts. You need to have a good national locust program that’s well-equipped, well-trained, well-funded so that they can respond to these situations. But it’s probably too idealist to think these nations are always going to have sufficient resources. At one point, it will probably overwhelm capacities — that’s what’s happened now in Kenya, Somalia, and Ethiopia. Then the international community has to step in.

The U.N. is calling for $138 million to mitigate the crisis. What does the allocation of that money look like?

Roughly, it’s about half for control operations — that’s upscaling the aerial control operations and getting in more aircraft, more ground logistical teams, supplemented by ground control like vehicles, sprayers, pesticide. The other half is basically to protect the livelihoods or to help those who have already been damaged to help them to recover. This can be seed packages to farmers if their initial crop has been lost. For pastures, it would be animal feed, because there’s a lot of pastoralists in the Horn of Africa who rely on pastures for their grazing animals.

What are the most concerning and the most hopeful aspects about the upsurge as it stands today?

The greatest concern is where it’s occurring, in the Horn of Africa — which is already extremely vulnerable to any slight disruption to food security and livelihood, simply because they’ve had a series of droughts in the past. Now they’ve got floods and heavy rains, and on top of that, locusts. No. 2 is that the swarms are in countries that either do not have very robust national programs or don’t have them at all. Kenya has seen locusts twice in the last 70 years — don’t expect it to have a strong locust program compared to a country that has to deal with locusts every year that’s much better.

Maybe the silver lining here is that they’re not going to stay in the Horn of Africa forever. Desert locusts are migratory in nature. When they move, they’ll move back north and into those countries where they are normally present — like Sudan, Eritrea, Saudi Arabia, Oman, Iran, Pakistan, India, and Egypt — and those countries have much stronger national programs to address them.

So There’s a Locust Plague Too?