In the heart of Kenya’s Naibunga Community Conservancy, a growing ecological threat is taking root — Opuntia engelmannii. This species of cactus has become a major invasive plant, impacting livestock health, grazing lands, and human wellbeing.
The Naibunga Community Conservancy is a community owned conservancy which seeks to conserve wildlife including elephant, eland, oryx, giraffe, gerenuk, lion, cheetah, wild dog, Grevy’s zebra, common zebra, and buffalo as well as grassland.
However, O engelmannii is threatening these efforts as the cactus can form dense monospecific stands, outcompeting more palatable grasses, herbs and shrub species. These dense stands can reduce the growth and presence of native flora and fauna, as well as preventing the free movement of larger wild animals which may also be harmed by the thorns.

Community began to notice its damaging effects
First observed over five years ago in the Doldol area, it spread rapidly across the region, primarily through natural dispersal mechanisms like birds, elephants, baboons, and human activities such as livestock movement. As it proliferated, the community began to notice its damaging effects.
Livestock health, particularly during dry seasons, suffered as O engelmannii outcompeted valuable forage species, leaving herders with limited grazing land and malnourished animals. Humans, too, face health risks, including skin injuries from the plant’s thorns and gastrointestinal issues from children consuming its fruit.
To combat this menace, the introduction of cochineal insects – including Dactylopius opuntiae (prickly pear cochineal) – which is showing some early promise. But before scaling up efforts, it was essential to gauge the community’s understanding and experiences with O engelmannii and its management.
CABI organized Focus Group Discussions
CABI scaled up the biological control efforts by establishing four additional screen houses for rearing cochineal insects. To support this initiative, CABI organized Focus Group Discussions (FGDs) with community members living near the newly established screen houses.
These discussions were instrumental in gathering valuable insights into local knowledge, community challenges, and their readiness to actively engage in and support biological control efforts.
With the negative effects of O engelmannii documented, the community began to look for ways to manage this invasive plant. Fortunately, biological control methods, specifically the introduction of cochineal insects, have been a proven solution in controlling another cactus species Opuntia stricta – also known as erect prickly pear.
The community’s experience with biological control methods, particularly cochineal, has fostered a sense of hope in the uptake of the technology. They see the insects as a sustainable, environmentally friendly approach that will not only tackle the invasive plant but also improve ecological and economic conditions in the region.
Strong willingness to engage in the biological control process
The community has expressed a strong willingness to engage in the biological control process. In the FGDs where over 200 community members took part, it was clear that there is a solid understanding of how biological control works.
The cochineal insects feed on the cladodes of Opuntia, weakening the plant and ultimately controlling its spread. The community’s previous successes with biological control for O. stricta, have built confidence in the approach, and many are eager to replicate these successes with O engelmannii.
However, the community also raised concerns and expectations. One major challenge identified is the lack of proper training on how to handle Opuntia safely and the cochineal insects effectively. There is also a need for protective gear, as handling the plant can be dangerous due to its sharp thorns.
Moreover, many community members, especially women, expect incentives such as reward for their labor in monitoring and distributing cochineal-infested cladodes, which will be vital to the programme’s success.
Collaboration and commitment shown by the Naibunga community
Winnie Nunda, Project Manager, Opuntia and Invasive Species Management, said, “I am proud of the collaboration and commitment shown by the Naibunga community in tackling the challenges posed by Opuntia engelmannii.
“The introduction of biological control, particularly using cochineal insects, offers a sustainable and environmentally friendly solution. Together, with proper training, resources, and continued community engagement, we are confident that we can manage this invasive species and improve the ecological and economic conditions for future generations.”
A key aspect of the biological control program is community participation in monitoring and ensuring its success. Community members are not only willing to engage in the stocking of the new screen houses but also to contribute to the collection and distribution of cochineal-infested cladodes in areas with severe O engelmannii infestations.
Spread of biological agents underscores the community’s commitment
Women, who make up the majority of those involved in the stocking process, play a critical role in the success of the programme. Their active participation in monitoring and ensuring the spread of biological agents underscores the community’s commitment to the initiative.

Harrison Rware, Monitoring, Evaluation, and Learning Officer, under the Opuntia and Invasive Species Management, said, “The success of this project lies in the active participation of the community.
“He further said that engaging community members in every step of the biological control process, from stocking the screen houses to monitoring the effectiveness of the cochineal insects, ensures both ownership and long-term sustainability.
“Our role in monitoring and evaluating these efforts is crucial to adapting and improving the approach as we move forward.”
While the community is eager to adopt biological control methods, there are some barriers to successful implementation. The distance between the villages and the new screen houses is a logistical challenge, making it difficult for community members to access them regularly for maintenance and monitoring.
Training and awareness on how to manage O engelmannii sustainably
Additionally, there is a pressing need for training and awareness on how to manage O engelmannii sustainably, beyond just the use of biological control.
Based on the insights gathered from the FGDs, several recommendations have been proposed to enhance the effectiveness of the biological control efforts and ensure their long-term success.
These include providing targeted training on biological control methods, focusing on handling, rearing, and distributing cochineal insects, as well as developing practical guidelines for managing O engelmannii.
It is also recommended that community members, particularly women, with gloves, boots, and other tools to safely manage Opuntia cladodes and prevent injuries, and the establishment of smaller, more accessible rearing units closer to villages to ease monitoring and maintenance efforts.
Ms Nunda added, “The Naibunga community has demonstrated a remarkable commitment to addressing the challenges posed by Opuntia engelmannii. Their deep understanding of the issue, combined with a strong desire to implement sustainable biological control methods, sets the stage for a successful intervention.
“By addressing the logistical, educational, and safety challenges, and incentives for labor, the community’s active involvement will be crucial to the success of this program. With continued support and engagement, Naibunga community can look forward to a future where Opuntia engelmannii is no longer a threat to their livelihoods and environment.”
Back in March 2024, CABI employed drones to meticulously map the Opuntia coverage across various clusters within the Naibunga Community Conservancy. Operating over predefined zones, the drones captured aerial imagery.
Subsequent analysis of these images involved the calculation of diverse vegetation indices to gauge water levels, chlorophyll content, spectral reflectance, and the overall condition of the prickly pear cactus.
Additional information
Main image: Community members stocking clean cladodes in the buckets before securing them in the screen houses for mass rearing (Credit: Harrison Rware).
Other relevant stories
‘Drones, insects and local community to tackle Kenya’s thorny problem.’
‘Biocontrol is most cost-effective strategy in fight against common pest pear Opuntia stricta.’
‘Loved and loathed: the bitter-sweet attraction of the world’s cacti in sharp focus.’
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