Residents of Mahiga-Meru village chase desert locusts using old aluminium cooking pots, iron sheets and twigs. [Dominic Kirui, Reuters]

After desert locusts invaded her farm in central Kenya, Mary Muthoni, 61, ran around her maize fields shouting and banging on an old iron sheet in a desperate attempt to drive them away.

"They came here yesterday evening and sat on top of these trees as though to rest there for the night," said the mother of seven, who lives in Mahiga-Meru village in Laikipia County.

"This morning, they decided to come down on my maize farm and started eating it, destroying the maize in the cobs and also the leaves,” she told Reuters last month.

The locusts crossed into Kenya from Somalia and Ethiopia at the end of last year and have so far infested 26 counties.

As the eggs they have laid hatch, food experts have warned a second wave of young locusts will further destroy crops and vegetation, intensifying hunger and environmental damage.

More than three million people already face serious shortages of food in the semi-arid areas due to alternating bouts of drought and flooding, according to the United Nations.

In a March update, the UN Food and Agriculture Organisation (FAO) said the locust situation remained "extremely alarming in the Horn of Africa", specifically in Kenya, Ethiopia and Somalia where widespread breeding was in progress.

New swarms were starting to form, "representing an unprecedented threat to food security and livelihoods at the beginning of the upcoming cropping season", the agency added.

Scientists say the appearance of the desert locusts may have been exacerbated by global warming and its impacts.

Hotter seas have brought more cyclones to the Indian Ocean, causing heavy downpours along the Arabian peninsula and in the Horn of Africa, creating ideal conditions for locusts to breed.

Kenya experienced high rainfall in the last quarter of 2019, together with strong winds, which supported the locusts' multiplication and spread, said William Marwanga, associate director for livelihoods and resilience at World Vision Kenya.

Officials also fear the locust invasions will do more harm to ecosystems already under stress from droughts and floods made worse by climate change.

"We are going to lose a lot of vegetation and our livelihood," said David Narokwe, disaster management officer for Laisamis sub-county.

He warned especially of the consequences for local livestock herders, who will struggle to find enough fodder for their animals as it is devoured by locusts, despite sufficient rains.

Control locusts

Newly hatched locusts feed on crops, shrubs and pasture before they can fly, decimating huge patches of land. The Government and its international partners, including the FAO, are working to control the locusts, both on the ground and from the air.

The FAO this month provided three more planes to assist with aerial spraying of pesticides. But with locusts feeding near villages and farms, it can be hard to use chemicals safely, while the areas affected are vast.

Problems like this mean residents in many parts of the country have been fighting the swarms with little direct help.

Some are chasing the insects away by screaming, hitting old pots, banging metal and shaking bells. Others are using tree branches and lighting fires to smoke them out.

“We have been taking turns around the village, assisting each other when (the locusts) settle," said Susan Wambugu, another resident of Mahiga-Meru.

"You also notice that they are competing with our sheep and goats for grass. This is just a satanic thing!" she exclaimed.