Opuntia Stricta – the Invasive Cactus Devouring African Rangelands

Livestock are Lazarus Lentula’s livelihood. For years, recurrent droughts have forced the herder in Kenya’s Laikipia County, like many others, to trek hundreds of miles across county lines in search of pasture.

Today, however, Lentula told FairPlanet, another threat is eating away what remains of his livelihood: the cactus species Opuntia stricta. A 2025 high-resolution mapping study identified the species as one of Kenya’s most widespread invasive plants, with Laikipia among the areas where it is particularly abundant.

A deadly threat to animals

During dry periods, when other forage becomes scarce, cows, goats and other livestock feed on the ripe fruit of Opuntia stricta. But the fruits are covered in tiny, barbed spines, which become lodged in the animals’ mouths, skin and digestive tracts.

A 2021 veterinary study of affected goats in Laikipia documented painful wounds and inflammation as well as severe damage to parts of the digestive system. In serious cases, the resulting pain and inability to feed can lead to severe emaciation and ultimately death.

‘I’ve lost several goats and sheep, my only source of income due to this plant which is difficult to eradicate,’ Lentula told FairPlanet.

In a 2026 survey of 155 residents around Il Polei in Laikipia, almost all of them herders, respondents collectively attributed the deaths of 1,225 cattle, 4,132 goats and 2,175 sheep over the previous five years to Opuntia stricta.

Dr Johnson Legei, a livestock and animal health veterinarian in Laikipia County, told FairPlanet that ‘the prickly spines on the fruits and leaves pierce animals’ mouths and eyes, causing blindness. This makes them reluctant to eat and drink, causing dehydration and death.’

In early 2026, Lentula lost six goats and two sheep worth US$430 due to the cactus, he told FairPlanet. He had planned to sell them during the April holidays to pay his children’s school fees. ‘I had to borrow money from friends and relatives, and it wasn’t easy,’ he said. ‘They too had suffered livestock losses from the Opuntia stricta.’

The threat is not limited to livestock. Previous research in Laikipia documented abscesses in the mouths of young elephants that died during a 2009 drought and suggested that cactus glochids could have contributed to the injuries. Jamie Gaymer, a wildlife conservationist with Kenya Rhino Range Expansion who previously spent more than 18 years at Ol Jogi Conservancy, told FairPlanet that Opuntia stricta is also altering wildlife dynamics in affected areas.

‘We have seen an explosion in the baboon population due to having year-round food through Opuntia stricta, which is drought resistant. This has a negative impact on some cliff-nesting bird species,’ Gaymer said.

Human displacement

Beyond the environmental and animal health impacts caused by Opuntia stricta, the invasive cactus is also contributing to human displacement as herders and their communities abandon heavily infested lands in search of new grazing areas.

‘The land here is already small, the cactus is swallowing the remaining portion, triggering internal migration,’ Francis Merinyi, an environmentalist and resident of Dol-Dol in Laikipia North, told FairPlanet.

According to Merinyi, people have left heavily affected areas including Makurian, Kurikuri, Morupusi and Il Polei since 2006.

A 2026 paper published in Frontiers in Conservation Science identifies invasive alien species as an overlooked driver of huma displacement and cites Opuntia stricta in Laikipia as one example. Referring to earlier research and reporting, the authors note that around two-thirds of Makurian Group Ranch in Laikipia had been invaded by Opuntia stricta and that about half of its 1,200 farmers and herders had moved elsewhere.

The economic toll

The economic impact of Opuntia stricta is already substantial in Laikipia. As dense stands of the cactus spread across rangelands, livestock can no longer reach part of the grass growing underneath and around them. A 2026 study led by researchers at the Centre for Agriculture Bioscience International (CABI) estimates that, under current invasion levels, forage inaccessible to livestock in Laikipia has a value of more than US$8.4 million.

But the economic impact of Opuntia stricta extends far beyond Laikipia. CABI’s study estimates the value of forage currently inaccessible because of Opuntia stricta at US$246.6 million across Kenya, Ethiopia and Tanzania. Assuming an annual spread rate of 10 per cent, the study estimates the present value of forage that could become inaccessible because of Opuntia stricta across sub-Saharan Africa at US$307 billion over the next 50 years.

‘The cost is far higher, the US$307 billion is just based on a reduction in the access to forage and it does not include costs to human and animal health,’ said Dr Arne Witt, CABI’s regional coordinator for invasive species, in an interview with FairPlanet.

Community-led biocontrol

Non-governmental organisations in partnership with government agencies and local communities have introduced an effective tool to control Opuntia stricta. The biological control agent Dactylopius opuntiae ‘stricta’ biotype is a host-specific cochineal insect that feeds on the cactus, weakening the plant and reducing its growth, flowering and fruit production.

With approval from the Kenya Plant Health Inspectorate Service (KEPHIS) and funding from Ol Jogi Ranch and CABI, the cochineal insects were imported from South Africa and placed in quarantine for trials at the Kenya Agricultural and Livestock Research Organization (KALRO). After additional host-specificity tests confirmed that the insect posed no threat to native plants or crops, Kenya’s National Environment Management Authority (NEMA) approved its release.

The cochineal was subsequently mass-reared and released at Ol Jogi. A 2020 field study found significantly fewer living cactus pads, flowers and fruits on plants colonised by the insect.

The approach has since expanded to neighbouring community conservancies. Ol Jogi has worked with neighbouring communities, including Naibunga, where residents rear and disperse the cochineal across affected rangelands. The insects are bred on Opuntia stricta cladodes in rearing houses before community members place infested cladodes on uncolonised cactus plants, allowing the cochineal to spread.

By 2019, the Northern Rangelands Trust reported operating 18 community greenhouses in the Naibunga conservancies, while 180 community members were employed once a month to disperse the cochineal across the landscape.

A 2026 survey around Il Polei suggests that communities are seeing tangible benefits. Eighty per cent of respondents reported declining cactus densities, while 90 per cent reported improved grazing and 95 per cent improved livestock health. More than four in five said they were themselves spreading the cochineal or encouraging others to do so.

Why an effective solution is still hard to scale

Even where effective biological control exists, funding, regulatory approval and limited technical capacity can slow its deployment. Maintaining and expanding community-based programmes requires significant resources. ‘The challenge is that those who will benefit from control often lack the financial resources to introduce, rear, release, and disseminate the cochineal,’ Witt told FairPlanet.

While the insects themselves are provided free to local communities, establishing the biological control programme in Laikipia cost around US$35,000, including regulatory approval, testing, mass rearing and initial releases.

‘Some countries have streamlined and efficient processes around the introduction of agents, while others have complicated and costly systems,’ Witt told FairPlanet. ‘Ideally, we need regional protocols for the introduction of agents.’

The challenge is therefore no longer finding an effective way to control Opuntia stricta, but creating the funding, capacity and regulatory conditions needed to scale it.

For herders like Lentula, the consequences remain immediate. Without sufficient funding and a more systematic effort to expand biological control across affected rangelands, families will continue to lose livestock — and with them, a vital source of income and security.