Some locusts may appear old and others pregnant but the invasion in Kenya is bound to get worse, a UN agency has warned.
The Food and Agriculture Organisation says a rising number of hopper bands and first-generation immature swarms continue to form in the country.
The FAO, in its latest alert, says widespread swarm breeding continues in northern and central Kenya, with further concentration expected in Marsabit and Turkana counties.
In a memo dated March 10, it noted that this may be supplemented by new-generation immature swarms arriving from Somalia.
“The situation remains extremely alarming in the Horn of Africa, specifically Kenya, Ethiopia and Somalia, where widespread breeding is in progress and new swarms are starting to form, representing an unprecedented threat to food security and livelihoods at the beginning of the upcoming cropping season," it said.
“Breeding continues in Ethiopia with a widespread swarm of instar hopper bands in Oromiya and SNNPR regions, including the Rift Valley.”
Immature swarms, the agency added, are also present in the south, where cross-border movements are likely from adjacent areas of Somalia and Kenya.
“Late instar hopper bands, maturing adult groups, fledglings and immature adult groups have been spotted in Somalia, Sudan and Eritrea,” the FAO said.
The desert locusts were first spotted in Wajir and Mandera counties and have made their way to Samburu, Isiolo, Garissa, Baringo, Turkana, Laikipia, Meru, Kitui, Embu, Machakos, Murang’a, Makueni and Kajiado.
Nairobi has tried to combat the worst locust invasion in 70 years through aerial spraying of pesticides but the number of those entering the country each day and breeding is overwhelming.
According to statistics from Samburu County's Special Programmes Department, the new generation bred in Kenya is already flying to Lekiji, Melepo Moo, Sesia and Mabati in Samburu East, decimating crops.
The voracious insects have a strong preference for graminaceous plants such as millet and maize.
Experts estimate that the insects are capable of destroying at least 200 tonnes of vegetation per day.
Swarms can travel up to 130km (80 miles) per day and a kilometre-wide swarm can contain up to 80 million locusts, according to the FAO.
Scientists from the Entomological Society of Kenya recommended advanced drone technology to contain the locusts devastating farms and grazing fields in different parts of the country.
They noted that aircraft deployed by the Ministry of Agriculture to conduct aerial spraying are insufficient for huge swarms.
According to Dr Muo Kasina, the society's chairman, the aircraft cannot areas such as deep valleys and mountain contours, where some of the locusts may be.
The FAO states that this is the worst invasion of desert locusts in the Horn of Africa in 25 years.
It poses an unprecedented threat to food security in the entire sub-region, with more than 19 million people in East Africa already experiencing a high degree of food insecurity.