Virulent locusts, which have invaded parts of Kenya in the past three weeks, now have experts warning that their presence there and to the north of the country and now moving south and east, pose an unprecedented threat to food security and livelihoods in the Horn of Africa.

United Nations’ Food and Agriculture Organisation on Monday described the infestation as “significant and extremely dangerous” warning of an eminent “food crisis in months to come” if control measures are not taken. FAO urged Uganda and South Sudan, where the locusts are headed, to remain vigilant.

Mandera, Wajir, Garissa, Moyale and Marsabit counties in Northeastern Kenya and down Southwest into central areas north of Mt Kenya, Isiolo, Samburu, Meru and most recently Laikipia and Kirinyaga counties are all infested. The Northern, South East and Rift Valley will be most affected.

Life cycle

This even as information from different scientists revealed that countries in the Horn of Africa had let the cusp of opportunity—which is the stage before wingless nymphs turn into adult locusts—when it is most logical to spray, escape.

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

“There has been increase in swarm activity during the past week in Kenya where numerous, large immature swarms are spreading from the initial invasion areas,” said FAO, in its Desert Locust situation update.

FAO’s senior locusts forecasting officer Keith Cressman, said there was increased concern as swarms in the northeast begin to mature.

“The concern is that once mature they will copulate and lay eggs in the ground,” he said.

“It is feared that there is egg-laying already happening in Kenya. Yet still more swarms continue to enter the North Eastern parts of Kenya on a daily basis from both Somalia and Ethiopia”.

FAO had earlier projected that breeding was going to be very low in Kenya.

Aerial spraying of pesticide is going on in Ethiopia (over 40,000ha sprayed in the past six months) and Kenya.

But, the “best time to spray locusts is during the nymph stage before they mature and can fly and scatter about. Once they are airborne control methods become harder and more expensive,” according to Mr Cressman who also termed current efforts in Kenya as “insufficient”.

It has been a testing time for Kenya, which before current aero spraying by some four aeroplanes begun on January 12, had resorted to desperate measures that included police shooting in the air, lobbing tear gas at the insects, panicky farmers clapping their hands, drumming, and whistling to try and chase away the armies of locusts.

In Somalia, where insecurity continues to inhibit control efforts, mature swarms in the Garbahare area near Mandera, are also expected to move into Kenya.

Desert locusts prefer to lay eggs in moist sandy soils. Once laid, the eggs will hatch in two weeks to produce locust nymphs that remain in the wingless form for up to a month and a half or two months, before becoming adults and forming swarms.

“These could give rise to hatchlings in the later part of next month and for the next two months. This means we will have an entirely new generation of swarms,” said Keith. “So we are looking at a rather protracted emergency for several more months that earlier thought.”

“There is prediction that (if no adequate control measures to exterminate the locusts in the already affected countries are effected), then they could move from Kenya to North Eastern Uganda in a week and then South East corner of South Sudan,” warned Mr Cressman.

“If they continually fly every day at the pace they are now moving at it would take a week before they are at Uganda’s borders,” he added.

Cereals target

The locusts invaded Mandera on December 28 before they spread to the neighbouring counties of Wajir, Garissa and Marsabit, and are moving into the interiors of the country with some swarms head down to Tana river and Lamu in the coast and others to Baringo, the Northern part of Rift Valley which is much more semi-arid.

Once in Baringo, according to Mr Cressman, “because there are crops throughout the Rift valley that they like, there is a risk that they will spread out through the region, the bread basket of Kenya. Locust devour mostly cereals.”

FAO has said the locusts are then expected to continue northwest to Turkana County in Kenya, while others will move west along the Ethiopian border, and then back into Southern Ethiopia.

But in Ethiopia, immature swarms continue to form and move in the eastern regions of Harar (East Harerghe) and Somali (Jijjiga and Warder, Kebridehar, Gode in the Ogaden), and further south in Oromiya (Bale) and have in last few days flown to the edge of the Rift Valley (Borena) near Teltele and Yabello, according to FAO.

Swarms in the Gode area are beginning to mature and more swarms to appear in Somali regions and in the southwest region of South Omo where they are likely to mature and lay eggs.

FAO has warned that in “all these affected areas, there is an unprecedented threat to food security and livelihoods.”

According to Michael Dyer, Borana Wildlife Conservancy managing director, who is also a member of Laikipia Farmers Association, this could get out hand even as they work with the government to handle the insects.

“Heavy rains, prevailing wind directions and excellent pasture in the north created a perfect storm for the locusts to thrive and spread. It is essential that we keep them out of intensive agricultural areas as well as the rangelands on which pastoralists and their cattle depend for survival—in both Laikipia and its surrounding counties,” he said.

This emergence could result in more hunger in parts of the Horn of Africa that were just beginning to recover from a succession of failed rains and ensuing drought and flooding that devastated food crops.

Experts estimate that the insects are capable of destroying at least 200 tonnes of vegetation per day. In just a week, residents in Isiolo report that 150 square kilometres of pasture have completely been destroyed by the locusts.

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

Former Agriculture Cabinet Secretary Mwangi Kiunjuri had expressed fears over the insects’ threat to the sector. Agriculture contributes 26 per cent of kenya’s GDP at Ksh2.9 trillion ($29 billion), according to last year’s estimates.

Origin—Arabian Peninsula

The locusts’ menace all begun in 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 for breeding in the sand desert of Arabia Rub' al Khali also known as the Empty Quarter that is extremely remote, hence nobody knew what was happening there,” explained Mr Cressman.

Because of the rains, the conditions were perfect for breeding for at least nine months. A generation of breeding lasts three months.

Meaning there were at least three generations of breeding that formed during this period. Experts say that with every generation of breeding, the number of locusts increases 20-fold.

“So we had this situation in the Peninsula, where locusts were increasing without any stop or control. Once it dried out in those areas about a year ago, swarms started to form and they left those areas some moving north to the interior of Saudi Arabia, to Iran, then to India and Pakistan. 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,” added Cressman.

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

In October, the swarms moved to the Ogaden desert in Eastern Ethiopia, from where they moved into Central Somalia, where there was more breeding during the last three months.

“The locusts just kept producing,” said Mr Cressman, “and at the end of year they moved to Southern Somalia from where they crossed over to Kenya. Other swarms moved from the Ogaden and Eastern Ethiopia also into Kenya.”

According to Cressman, the swarms in Kenya are a result of the breeding that has been going on now for the last number of months, made worse by the cyclone last month that allowed conditions continued breeding until June.

Wind-assisted relocation

Locusts are pushed by wind. They cannot fly against the wind. And the weather in the regions where they have been has been particularly windy.

“They are a victim of the wind direction. The wind from October to February has been blowing from north to south over the Horn of Africa. That means that any locusts out there in Ethiopia or Somalia will continue to be blown into Kenya,” Mr Cressman added.

As we continue into late January and February, the winds will start to change and blow in the opposite direction from the north to the south. This will stop any southerly migration.

Compared with the most recent major upsurge of locusts, during 2003-2005, about 12 million hectares had to be treated in North West Africa, Sudan, Egypt and parts of Saudi Arabia.

Further afield, according to FAO, in Southwest Asia, swarms are still present on both sides of the Indo-Pakistan border but numbers are declining due to control operations and migration to the southern Iran where swarms that already reach the southeast have matured and laid eggs. In the past few days, unusually heavy rains in southeast Iran, caused flooding and loss of life.

On the southeast coast near Chabahar, more rain fell in a day and half than what normally falls during the entire year. And it is expected that once floodwaters recede, ecological conditions will be favourable for several months of breeding that is expected to cause a significant increase in locusts by spring.

Important breeding continues in the winter breeding areas along the coastal plains of the Red Sea where control operations are in progress against hopper groups, bands and adult groups in Saudi Arabia (8,000ha), Eritrea (3,500ha), Sudan (1,800ha) and Yemen (1,080ha).

According to FAO over two million hectares of the affected lands across their path have been treated in the past 18 months.