EXPLAINER: Desert locust invasion

In Summary

• The situation was worsened by two cyclones that caused heavy rains in the Empty Quarter on the Arabian Peninsula in May and October of that year.

On Monday, January 13, the desert locust invasion spread to Lakipia and Meru counties, bringing to eight the number of regions affected.

It made true Kenyan insect scientists January 9 warning that the desert locusts, which had by then invaded Mandera, Wajir, Marsabit, Isiolo, Garissa and Samburu could spread.

Entomological Society of Kenya chairman MuoKasina said the short rains were favourable for the mating and breeding of the insects.


The government has grappled with how to control the locusts using aerial spray since they were sighted in Northeastern.


Origins of the current outbreak

The Food and Agriculture Organization desert locusts watch reports that the current outbreak occurred along the Red Sea coast around May 2018.

The situation was worsened by two cyclones that caused heavy rains in the Empty Quarter on the Arabian Peninsula in May and October of that year.

The rains caused massive breeding over three cycles that went unnoticed. Thereafter, numerous swarms began to move south in January to March last year.

Other two cycles of breeding followed. The swarms then drifted with the winds to Iran, and ended up on the border between Pakistan and India in June.


They then migrated to Yemen where political instability and war prevented surveillance and control. Subsequently they crossed the Gulf of Aden into Ethiopia and Somalia.

Once they reached Somalia, it seemed inevitable that they would reach Kenya.

On December 28, several large immature swarms appeared in Northeastern near the Somali border of Mandera and Elwak, according to the FAO.

As of January 9, when the scientists from the society of entomologist spoke in Nairobi, six counties had been affected. They warned the swarms could spread across the county.

What are desert locusts?

According to Hojun Song, an entomologist at Texas A&M University, locusts are a type of grasshopper capable of undergoing reversible changes to their physical appearance and behaviour based on population density.

The National Geographic says locust swarms are present in 60 countries inAfrica, the Middle East, and Asia, and can cover one-fifth of Earth's land surface.

The desert locusts are called so because when they are not migrating, they breed in the wet sands in the deserts. They are pink when not ready to lay eggs and take two weeks to mature to adults and turn yellow.

A swarm can be 740 square kilometres in size and carry between 40 and 80 million locusts into less than half a square mile.

Each locust can eat its weight in plants each day. A tonne of locusts can consume the same food per day as 20 elephants or 25 camels or 2,500 people. They can destroy huge farmlands in such a short time, hence, cause starvation.

A desert locust has a lifespan of three to four months.


Sceintists say the best way to control locust infestation is to prevent their breeding.

Christian Koiman, a retired locusts expert says that a single female locust can lay 300 eggs.

“After mating, the males die leaving the females to lay eggs. The eggs hatch in two-three weeks and the larvae take two to three weeks to become adults,” Koiman says.

MuoKasina says, “Focus on the potential breeding habitats and kill the populations that emerge from them. This will ensure we don't allow the eggs laid in the country to hatch and affect vegetation.”

The government and the Desert Locust Control Organisation of East Africa have been working together to provide aerial spray to control the locust in the affected counties.

John Nderitu, an insect scientist from the University of Nairobi, encourages the use of a combination of pest management methods to limit the population.

“We recommend pulling together of different methods to ensure we manage the insects, including mechanical and chemical control, as well as traditional methods such as harvesting the insects for food and scaring them away,” he says.

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