The UN will test drones equipped with mapping sensors and atomisers to spray pesticides in parts of east Africa battling an invasion of desert locusts ravaging crops and exacerbating a hunger crisis.
Hundreds of millions of the voracious insects swept across Ethiopia, Somalia and Kenya in what the UN calls the worst outbreak in 25 years, with Uganda, Eritrea and Djibouti also affected.
Aerial spraying is being done but experts say the scale of infestation is beyond local capacity as desert locusts can travel up to 150 km in a day.
They threaten to increase food shortages in a region where up to 25 million people are reeling from three consecutive years of droughts and floods, say aid agencies.
Keith Cressman, senior locust forecasting officer at the UN Food and Agriculture Organisation (FAO), said specially developed prototypes that can detect swarms via sensors and adapt speed and height would be tested.
“No-one’s done this with desert locusts before. So we have no proven methodology for drones spraying on locusts,” said Cressman.
“There are small atomiser sprayers for drones. With locusts, we don’t know how high and how fast to fly.”
The swarms – one reportedly measuring 40 by 60 km – devoured thousands of hectares of crops, including maize, sorghum and teff, and ravaged pasture.
By June, the fast-breeding locusts could grow by 500 times and move into South Sudan.
The impact on the region’s food supply could be enormous – a locust swarm of a square kilometre is able to eat the same amount of food in one day as 35,000 people, says the FAO.
CAN DRONES WORK?
Climate scientists say global warming may be behind current infestations, which hit parts of Iran, India and Pakistan.
Warmer seas resulted in a rise in the frequency of cyclones in the Indian Ocean. This caused heavy downpours along the Arabian Peninsula, creating conditions for locust breeding in the deserts of Oman, Yemen and Saudi Arabia.
Researchers are increasingly looking to technology to provide early warning signs and control locust outbreaks amid fears climate change could bring more cyclones.
Officials in Kenya say drones could play an important role given a limited number of aircraft.
“Every county wants aircraft. We have five at present and they can only be in one location at one time,” said David Mwangi, head of plant protection at Kenya’s ministry of agriculture.
“We have not used drones before, but I think it’s worth testing them.”
Existing drone models are restricted in terms of weight they carry and distances they can cover due to size and limited battery life, say entomologists and plant protection researchers.
Another challenge for drone use in emergencies is lack of regulation. Many east African countries are in the early stages of drafting laws, prohibiting usage unless in exceptional circumstances and with strict approvals.
That makes it harder to deploy larger drones, with petrol engines capable of carrying tanks of up to 1,500 litres and travelling up to 500 km and often require special approval.
Drones can also be used in the aftermath of an infestation.
“The other use case for drones is in post disaster mapping,” said Kush Gadhia from Astral Aerial Solutions, a Kenyan firm using drones to address development challenges.
“Governments need to know the extent of damage. Combining large satellite maps with smaller drone maps – with higher resolution images – will give more accurate assessments on the extent of crop loss and health.”