Demystifying the locust plague: Why it's all happening now

Locusts on a tree in Kanukurmeri village in Turkana County on January 20. Locusts have invaded different parts of the country. PHOTO | JARED NYATAYA | NATION MEDIA GROUP

It is fast, ferocious and will stop at nothing. It is called a desert locust or, scientifically, Schistocerca gregaria. The desert locust, the insect wreaking havoc across the country, is one of the most destructive species. It’s greatest assets being agility and endurance, enabling it to remain in the air for long periods of time. Thanks to this, the desert locust can cover 150km per day at a speed of 16km/hr, destroying everything in its path.

For an animal so small, the desert locust has an appetite of a mammoth. There is no better evidence of this than the now bare fields in different parts of Kenya that were once covered with plants.

A large desert locust plague can contain up to 150 million individuals per square kilometre, with half a million locusts weighing approximately one tonne. One tonne of locusts eats as much food in one day as about 10 elephants, 25 camels or 2,500 people.

Experts estimate the insects are capable of destroying at least 200 tonnes of vegetation per day.

In Mandera, Wajir, Garissa, Moyale, Marsabit, Isiolo, Samburu, Meru and most recently Laikipia and Kirinyaga counties, locusts are crawling everywhere. Farmers are at the mercy of the pest, with the swarm raiding crops and pasture, threatening food security. Now there are fears of a human-wildlife conflict as animals could be forced to forage on farmlands.


Agriculture officials estimate that 500,000 hectares of pasture and cropland have so far been destroyed by locusts in Mandera, Marsabit, Wajir, Isiolo, Meru and Samburu counties. By the end of last week, the insects had covered more than one million hectares of land in Kenya.

Wajir County’s Agriculture minister Ahmed Shariff says the locusts destroyed 250,000 acres of pasture and 7,400 acres of crops in the area, while in Isiolo and Meru, the locusts have gone through more than 37,000 acres of pasture, leaving thousands of livestock staring at starvation.

In Mandera, where Governor Ali Roba says there has been no aerial intervention, the locusts have covered millions of acres of pasture land.

Marsabit Agriculture minister Mohammed Omar says more than 250 acres of maize, bean and pea farms were destroyed at Dogogicha and Sagante-Jaldesa within 15 minutes.

In just a week, residents of Isiolo report that 150 square kilometres of pasture has been destroyed.

So far, the destructive pests, according to county officials, have covered over 4,000 square kilometres of land in Garbatulla and Merti sub-counties.

This is not the first time the country is grappling with a locust problem and the menace is not confined to Kenya’s borders. Kenya was last hit by a locust plague in the 70s, according to the United Nations’ Food and Agriculture Organisation (FAO).

The current outbreak has also affected parts of Somalia, Ethiopia, Sudan, Djibouti and Eritrea. The swarm could be headed for South Sudan and Uganda, the Intergovernmental Authority on Development (Igad) has warned.

In Ethiopia and Somalia, more than 170,000 acres of crops and pasture land had been wiped out by December last year, according to the Igad Centre for Pastoral Areas and Livestock Development.
Over the last two months, the infestation has affected several states in Ethiopia and has seen farmers lose nearly 100 per cent of their crops.

The swarms now in Kenya had been travelling for months from country to country. Originating at the India-Pakistan border, the insects migrated into Somalia and Ethiopia, where they destroyed nearly 175,000 acres of farmland in the two countries.

From Somalia, they entered Kenya through Mandera and El Wak in December last year. The swarms that entered the country were in the adult stage, but immature, meaning, they were not ready to mate and lay eggs. However, this could soon change.

Due to this, Agriculture Cabinet Secretary Peter Munya has termed the insects a threat to the economy and the sector. Agriculture contributes 26 per cent of Kenya’s GDP at Sh2.9 trillion, according to last year’s financial report. “It is high time we look at other ways of tackling the locusts. They are the biggest threat to the agriculture sector,” he said.

Earlier, FAO had described the infestation as “significant and extremely dangerous”, warning of an imminent “food crisis in months to come” if control measures are not taken.

Already, FAO has urged Uganda and South Sudan, the pests’ next target, to remain vigilant, warning this invasion is the worst in 25 years.


But, what could have triggered the invasion?

University of Nairobi Head of Insect Science, Dr George Otieno, says desert locust invasions usually occur after a drought that is followed by rapid vegetation growth.

“The favourable conditions brought about by heavy rains experienced during the short rain season last year, which brought forth lush vegetation, has made it possible for the insects to thrive and they will be here until February,” says Dr Otieno.

FAO’s locusts forecasting senior officer Keith Cressman says the swarms in Kenya are a result of the breeding that has been going on for the last couple of months, made worse by the cyclone last month that allowed favourable conditions set to continue until June.

Contrary to the assumption the invasion is a surprise, Cressman clarifies that the menace began between May and October 2018 when two consecutive cyclones in the Indian Ocean brought heavy rains to southern Arabia. “These two cyclones brought with them heavy rains and very good breeding conditions in the sand desert of Arabia Rub’ al Khali that is extremely remote, so nobody knew what was happening there,” he says.

The breeding conditions were perfect for at least nine months. A cycle of breeding lasts three months. “So, we had this situation in the Peninsula, where locusts were increasing without any control measure. Once the Peninsula dried about a year ago, the swarms started forming and left those areas. Some moved north to the interior of Saudi Arabia, to Iran, then to India and Pakistan,” he says.

“But, another portion of the swarm moved south into Yemen this past year, where the conflict did not allow for any control measures. So, there was more breeding in Yemen and they started leaving the country in June crossing to the Horn of Africa.”

The locusts reached North-Eastern Ethiopia and parts of northwest Somalia six months ago.

In October, the swarms moved to Ogaden desert in Ethiopia, from where they moved into Central Somalia, where there was more breeding during the last three months. “The locusts just kept reproducing,” adds Mr Cressman, “At the end of year, they moved to Southern Somalia from where they crossed over to Kenya. Other swarms moved from Ogaden and Eastern Ethiopia into Kenya.”

Authorities say the hoppers are headed further southwesterly and east of the country and could be in Uganda and South Sudan in a week’s time.

And things might get worse, according to the scientist. Between late January and early February, there will be a change in weather. The winds will blow from the north to the south. This will stop any southerly migration since the locusts rely on the wind to migrate.

“They are victims of wind direction. From October to February, the wind has been blowing from north to south over the Horn of Africa. That means any locusts in Ethiopia or Somalia will continue to be blown into Kenya,” he says.

Abdurahman Ismail, a migratory pests expert and director of the Somaliland Environmental and Agricultural Protection Institute, concurs. The threat is not over yet. The swarms in Kenya are said to have laid eggs in northern Somalia that are now hatching. This means the adults might migrate again, in even larger numbers, into Kenya.

“Locusts are highly mobile and destructive,” he says. “The situation is very, very serious.”

The CS, announced last week that the government has allocated nearly $300,000 (Sh30.3 million) to fight the pests.

Kenneth Mwangi, a satellite information analyst at Igad Climate Prediction and Applications Centre, says a late response to early warning information in the region is to blame for the invasion.

Besides the slow response to early warnings issued by FAO in October and December last year, authorities are now fighting accusations of using ineffective methods of eliminating pests and lack of resources, setting up the region for acute famine.

The government has since resorted to buying stronger chemicals for aerial spraying since the locusts are still active, feeding and moving despite being sprayed on with the insecticides for two consecutive days.


An official from the Agriculture ministry says the government is in plans to secure more resources from the Treasury for the hiring of more aircraft and buying of pesticides to bolster surveillance efforts. “We are looking for Fenitrothione after realising the Fenthione we were about to buy is not effective,” says the officer, referring to the brands of the chemicals in use, which are supposed to immobilise the insects, rendering them unable to move to the next feeding zones.

When HealthyNation asks Dr Muo Kasina, Entomological Society of Kenya chairman, why it is difficult to control the desert locust he clarifies that once developed, a locust plague is almost impossible to stop or control.

“The locusts enter the gregarious phase if there is sufficient rainfall that guarantees enough vegetation for the young ones and the ground is moist for egg development. The insects then breed and grow their numbers. With the population being high, they change their behaviour and aggregate, eating and moving en masse,” says Dr Kasina.

He advises that the only way to prevent them from progressing to the gregarious phase is to take measures to reduce their numbers with continuous monitoring.

The lifecycle of a locust consists of the egg, nymph and adult phase. The egg takes about two weeks during favourable conditions to hatch into a nymph. Both nymphs and adults are feeders.

However, the nymphs (also known as hoppers) do not have wings and become adults 30-40 days after hatching. The young adults take about three weeks before they are ready to mate and lay eggs. Adults live for three to five months.

To manage the locusts, Dr Kasina calls for control measures, including destroying egg masses laid. This is done by invading swarms, digging trenches to trap nymphs, using hopperdozers (wheeled screens that cause locusts to fall into troughs containing water and kerosene), using insecticidal baits, and applying insecticides to both swarms and breeding grounds from aircraft.

He says the best time to spray locusts is during the nymph stage before it can mature and fly. “Once airborne, control methods become harder and more expensive,” says Dr Kasina, terming current efforts to stop the invasion insufficient.

“Considering their flight capability, it is advisable to report as quickly as possible any sighting of a swarm to the nearest county or national government officer, or place images in social media groups. This will allow the government to respond in good time.”

He also advises that chemical control should be managed centrally; there’s no need for an individual farmer to use such means as it may not work. “Making loud noises scares away the locusts and increases the rate at which they spread,” he warns.