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Desert locust swarms

Smart technology tackles East Africa’s locust swarms

Image credit: FAO/Sven Torfinn

Swarms of desert locusts have destroyed swathes of crops in Kenya and other east African countries this year. We speak to the people on the front line of the battle to stop the swarms with the help of high-tech solutions.

“Once our scouts locate a swarm, they go in the early morning and catch individual locusts” says Edward Amoah Idun, a Master’s student at Penn State University, Pennsylvania. Idun’s Kenyan colleagues then glue a 150mg tracking device to a chosen insect’s thorax, looking like a tiny backpack. Once the swarm takes off, the team follows them on motorbikes across rugged landscapes in the north of the country, using the tracker to follow where they fly.

Idun’s research will help us learn more about how swarms of locusts behave. “For decades, our understanding was that locusts moved with the wind,” he explains, yet if this was the only factor, we would expect far more of them in Ethiopia than there currently are. “Our research aims to find out how topography, vegetation, humidity and rainfall also affect their behaviour.”

This is one example of how high-tech solutions are being deployed to address a catastrophic locust outbreak – the worst in decades – that has swept through the Horn of Africa, parts of the Middle East and South Asia this year. While the dry season (roughly May-October) slowed their spread, the current rainy season provides perfect conditions for breeding.  

The desert locust is a normally solitary insect which actively avoids its own kind. However, under certain conditions, these creatures become social and form swarms that grow exponentially. A series of unusual weather patterns in the Indian Ocean in 2018-2019 may be behind the current situation. Heavy rains inundated a normally arid part of Yemen, allowing the insects to spawn in greater numbers than usual. As the population exploded, waves of locusts migrated to surrounding regions.

Swarms can reach astronomical sizes, with tens of billions of the insects covering miles of vegetation and devouring everything in sight. A locust can eat its bodyweight in food each day – about 2g –leaving farmers in penury overnight.

“In the past, researchers would trek across the desert on camels to track locusts” says Keith Cressman, a locust expert at the UN’s Food and Agriculture Organisation (FAO). Until the invention of pesticides, the only real way to deal with the pests was fire, or to try and bury them in ditches.

Spraying operations against locusts

Image credit: FAO/Isak Amin

Fortunately, things have improved. We now know how to kill locusts using specific types of pesticide and spraying techniques (either delivered on foot, from the back of a pick-up or by air). If they are found and destroyed while still in the egg or as young flightless ‘hoppers’, it is possible to stop swarms spreading – because winged adults can travel over 100km per day.

The difficult part is finding them – especially in vast underpopulated regions. This is where technology can help.

Starting ‘on the ground’, Cressman describes eLocust, an app that lets scouts in the field travel to potential outbreaks then beam the precise location to a central command which will send out a pesticide-carrying cavalry. In its latest iteration, eLocust3m (created in collaboration with PlantVillage, an agricultural tech organisation spun out of Penn State University), the app can be downloaded by anyone with a smartphone.

Melodine Jeptoo has been co-ordinating eLocust3m scouts in Kenya this year and explains how it works. “We provide local scouts with smartphones and they are sent out to look for locusts” she says. Because the scouts are recruited locally, they know local languages and communicate easily with pastoralists who may have spotted the signs of locusts nearby. “The scouts take a photo of the insect and fill in data about life stage and air carriage” she explains. The app also records GPS coordinates and prompts users to describe nearby landmarks to help the authorities locate the bugs.

This data is shared with governments and the FAO and is also beamed back to Penn State where computers use artificial intelligence to scan images of the locust photos – and make sure it is in fact a desert locust.

Professor David Hughes, who founded PlantVillage reports the app has been downloaded from Kenya to Nepal and recorded some 17,000 outbreaks.

The FAO has also begun experimenting with drones to pinpoint pests. When hunting for eggs and hoppers, you need to cross the desert looking for patches of greenery. This is “like finding a needle in a haystack” says Cressman, and in the past, local teams would be forced to travel across swathes of desert, making best guesses about where to find vegetation that young hoppers begin feeding on.

Now, the FAO is trialling a customised fixed-wing drone to make this process more efficient. The drone can fly up to 100km and identify patches of greenery where locusts might be growing. That means field teams can head straight for danger spots and nip swarms in the bud.

Then there are satellites – the FAO receives data from Nasa to identify where locusts might be spawning. Female locusts like to lay their eggs in moist sandy soil, and Nasa’s satellites can identify average soil moisture over hundreds of miles of land. This can then be fed into the FAO’s modelling platforms to help predict where future outbreaks will occur.

How much of an impact is this technology having? Despite the size of this year’s outbreak (which has been ‘helped’ by conflict in Yemen and unusual weather patterns) Cressman believes the tech makes a big difference. “Since we have been using more technology over the last 20 years, governments have detected and controlled many more outbreaks than they would have.” And Hughes of PlantVillage says the eLocust3m and other technology may have protected food for some 10 million people.

Right now, Kenya and the Horn of Africa is in its short rainy season (Oct-Dec), and so damp soil and greenery will create the perfect conditions for next generation of locusts to breed. But, armed with an arsenal of clever technology and pesticide, governments, farmers and millions of people will be hoping the next swarm can be stopped in its tracks.

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