October 30, 2025 | Africa
A new CABI-led study has revealed a significant improvement in farmers’ perceptions and understanding of biological control methods, following their active involvement in the early stages of a biological control initiative.
Published in the journal African Entomology, the research examined changes in farmers’ knowledge, attitudes, and practices toward the biological control of papaya mealybug (Paracoccus marginatus) after the release of the parasitic wasp Acerophagus papayae in Kenya’s coastal counties of Kilifi, Kwale, and Mombasa.
Enhanced Awareness and Crop Productivity
The study, conducted between 2021 and 2022, surveyed 141 farmers before and after the release of A. papayae. Findings showed a 12% increase in awareness of biological control, along with a marked improvement in farmers’ perceptions of its effectiveness and impact on crop productivity.
A difference-in-difference analysis indicated that treatment farms—those where the wasp was introduced—recorded an average increase of 196 kg in papaya production compared to control farms. Moreover, control farms experienced an income loss of USD $94 on average, underscoring the economic benefits of adopting biological control.
Farmers’ Changing Perceptions
Over the study period, farmers’ perceptions of biological control attributes improved considerably:
- 17% increase in viewing it as an effective pest control method.
- 10% increase in belief that it enhances crop productivity.
- 8% increase in perceiving it as an affordable pest management option.
There was also a slight reduction in the perception that biological control is slow-acting or labour-intensive. However, the study noted gender differences in perception—men generally demonstrated more positive attitudes toward biological control than women.
For instance, men were 18–21% more likely to perceive biocontrol as effective, safe, and affordable. Nonetheless, women’s positive perceptions improved significantly over time, with the percentage of women viewing biological control as effective rising from 29% in 2021 to 37% in 2022.
Addressing Pest Threats and Promoting Sustainability
The papaya mealybug, which invaded East Africa between 2015 and 2020, has caused devastating yield losses of 57–91% and annual household economic losses of approximately £2,224 per hectare. To date, nearly half of the affected farmers rely on chemical pesticides, which harm insect biodiversity and pose risks to human health.
Biological control offers a sustainable and eco-friendly alternative. The introduction of A. papayae, a natural enemy of the papaya mealybug, has proven effective in managing pest populations in several countries, including Ghana, Sri Lanka, Pakistan, and Puerto Rico.
Empowering Farmers Through Engagement
Lead author and CABI Project Scientist Kate Constantine emphasized the importance of farmer engagement, stating:
“The findings highlight the need for continuous awareness campaigns and gender-responsive farmer education on the use and benefits of biological control, as well as how to minimize dependence on chemical pesticides.”
She further noted that sustained interaction with farmers will strengthen their knowledge and capacity, ultimately enhancing the success of biological control programs across sub-Saharan Africa.
National Implementation and Future Outlook
Following the success of the initiative, the Kenya Standing Technical Committee on Imports and Exports (KSTCIE) has approved the widespread release of A. papayae across all papaya-growing counties in Kenya.
CABI scientists, in collaboration with the Kenya Agricultural and Livestock Research Organisation (KALRO), Kenya Plant Health Inspectorate Service (KEPHIS), and the National Museums of Kenya (NMK), continue to monitor and assess the wasp’s performance as part of integrated pest management (IPM) strategies.
This milestone demonstrates the value of participatory approaches in pest management and reaffirms biological control as a key tool for achieving sustainable, environmentally safe, and economically beneficial agriculture in Africa.
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