To Dr Roger Price, the swarms of brown locusts he has seen in the Karoo look like clouds of smoke billowing on the horizon, turning darker and lighter as the insects sweep over the land.
“When a brown locust swarm is spread out, it can easily be 30km long,” says Price, the research team manager for plant health and protection at the Agricultural Research Council. “They can fly over 100km a day. They just go on for hours.”
The locust pot is stirring in South Africa, he says.
“Our main concern is the brown locust, which is endemic, and only found in the Karoo area and southern Namibia — and it’s a very serious pest once it gets going. It costs the country millions to keep it in the Karoo, to control it and to prevent it from escaping and invading crops in the Free State.”
Price explains the conditions for a large-scale outbreak are favourable after good rains ended a long dry spell in the drought-stricken Karoo, prompting long-dormant egg populations in the soil to hatch into marauding hopper bands.
About 130 farms in the eastern Karoo are already infested.
“This year’s outbreak seems to be early and I’ve noticed that the rainfall predicted for the Northern Cape is unusually heavy for this time of year so the conditions are good.”
The Karoo is the scene of an immense locust problem, he says, but it’s hidden.
“Nobody really knows about it in the cities until the locusts occasionally fly out of the Karoo once every 10 years over Bloemfontein or Kimberley. We have to spray pesticides, which are not healthy for the environment and it just costs an awful lot of money.”
A resurgence in East Africa
At first, to a farmer, it looks like a promise on the horizon: a dark rain cloud, sometimes so big it can block out part of the sun.
Then the penny drops.
Keith Cressman, senior locust forecasting officer at the Food and Agriculture Organisation (FAO) of the United Nations says it’s a moment of pure horror when the farmers realise what those clouds really are.
“You see it’s not a rain cloud but a cloud of insects and realise this is a desert locust swarm. They will eat absolutely everything. By midday, you’ve lost your entire crop for the year and maybe for the next year. It’s devastating.”
This year, destructive, desert locusts have swarmed in gigantic numbers in countries including Kenya, Somalia, Ethiopia, Uganda, Somalia and Eritrea, gobbling valuable cropland and decimating livelihoods.
In January locust swarms that invaded northern Kenya were as big as the country of Luxembourg.
But while aerial and ground operations have exterminated an estimated 500-billion locusts in the past 10 months, there are worrying signs of resurgence.
Early, ongoing rains have led to a new cycle of breeding with fresh swarms forming in Ethiopia, Somalia and Yemen, warns the FAO.
In good conditions, desert locusts reproduce like wildfire — their numbers surging by a factor of 20 with each three-month reproductive cycle.
The new wave wasn’t unexpected, says Cressman, who describes desert locusts as “professional survivalists. When there’s really good rain, the locusts respond.”
Winds over the northern portion of the Horn of Africa now starting to blow southwards again could trigger a re-invasion in Kenya later this year.
But with almost a year of locust-fighting experience under their belts, affected countries are in a far stronger position to manage and contain the infestations, says Cressman.
“Last year this time, countries such as Somalia, Ethiopia and Kenya weren’t very well prepared. Now, they’re well-equipped to manage and respond to this type of breeding and any kind of invasion that might occur by the end of the year.”
Somalia, he adds, has not used one drop of chemical pesticides, wiping out its locusts with biopesticides made from a natural fungus, which only attacks locusts and grasshoppers.
Unusual weather a factor
The desert locust outbreak, says Cressman, started with two cyclones that brought heavy rains to the same region of the Arabian Peninsula last year.
“That’s already kind of strange. In 2019, there were something like eight cyclones in the western Indian Ocean. Normally there’s zero or one. Then we had a cyclone in December — in the beginning of winter, which is very unusual.
“It could just be a temporary anomaly. What I worry about is if we continue to see this trend — increased cyclones in the western Indian Ocean — that will have impacts on locust infestations in the Horn of Africa that can lead to more emergencies and upsurges that we’ve seen this year.”
In the future, with more unpredictable weather, more opportunities for pest outbreaks will emerge, says Price. “Not just locusts but everything from mosquitoes to army worms. They respond very quickly to dramatic, unusual weather patterns. So it’s going to get worse and is not going to be easy to predict.
“The problem is that for many years migratory pests are at a low ebb. So, the ability to predict them and combat them is weakened because there isn’t any investment in technologies and stocks of pesticides. When they do arrive, it’s a surprise and we can’t cope. Boom-and-bust funding is the typical response.”
Professor Frances Duncan of the school of animal, plant and environmental studies at the University of the Witwatersrand, agrees. She explains how unusual climatic conditions are driving outbreaks of African migratory locusts in Botswana, Namibia, Zambia and Zimbabwe, through unusually high rainfall and flooding, as with desert locusts.
The FAO, which launched an emergency response in September, has warned seven million people are at risk from the outbreaks in southern Africa, facing threats to their food security and livelihoods.
“What’s really coming home is that there’s not enough surveillance. Unfortunately governments forget that the locusts are around. But we must remember swarms are part of the ecology. Swarms of locusts were mentioned in the Bible so they’re not a new phenomenon.”
Rise of the grim reapers
More than 860 000 hectares of land in 10 countries have been surveyed and treated for locust infestation since January to counter the desert locust outbreak. Control operations have prevented the loss of 1.7-million tons of cereal — enough to feed more than 10-million people a year — in countries already hard hit by acute food insecurity and poverty. Kenya has contained the locust to just two northern counties. West Africa is no longer at risk of invasion. — Food and Agriculture Organisation of the United Nations.