14 October, 2025
Agency report, Kenya
A nature-based solution is demonstrating impressive outcomes in supporting farmers in Kenya, Uganda, and South Sudan in sustainably revitalising their pawpaw(papaya) crops affected by the papaya mealybug pest.
The papaya mealybug, known scientifically as Paracoccus marginatus is a devastating pest which is wreaking havoc across East Africa, slashing yields, reducing orchard lifespans, and undermining food security and livelihoods.
Dr Selpha Miller, an Invasive Species Management expert spoke in an interview with the News Agency of Nigeria (NAN) at the Crop Protection Biological Control Laboratory on Tuesday in Kenya.
She said the solution was a classical biological control strategy for papaya mealybug using the parasitic wasp, Acerophagus papaya, adding that Nigeria was not exempt from the pest.
The visit to the laboratory was a pre-tour of the World Congress of Agricultural Journalists event scheduled to officially take place from October 15 to October 18, 2025, in Nairobi, Kenya.
According to her, pawpaw is a very important staple fruit in Eastern Africa that serves as food and cash crop, and the pest also destroys other crops such as cassava among others.
She disclosed that the pest originated in Central America but first detected in Africa in 2010, that the pest reached Kenya in 2016 and Uganda in 2021.
She said the potential crop losses of up to 91 per cent was valued at around 2, 223 pounds per hectare annually.
Miller disclosed that Kenya, in partnership with CABI, a centennial non-profit organization, began using the parasitic wasp, parasitoid to control pests in coastal and inland areas.
She said when every other method failed, parasitoid became the most effective method to use in controlling invasive pests.
“Mass release of the parasitoid commenced from December 2021, and, so far, 1,822,625 parasitoid individuals have been supplied to 990 farmers in nine countries.
“A total 3679 farmers in all the nine countries have been trained and sensitised about papaya mealybug control using Acerophagus papaya parasitoid.
“The project has also built capacity of 260 extension officers and 29 crop inspectors in the countries on papaya mealybug biocontrol,’’ she said.
The CABI scientist noted that the parasitoid has successfully established in the coastal region of Kenya, reaching over 70 per cent parasitism.
According to her, in just a year, papaya production recovered to production levels before papaya mealybug invasion.
Miller hinted that following pesticide withdrawal by participating farmers, a high number of predators and previously absent natural enemies have been observed at release sites.
Accordingly, that a full socioeconomic assessment of the project was conducted in March 2025 following up from a baseline in 2019.
She added that the results showed the biological intervention increased papaya yields and income by 19, and 57 percent respectively.
The scientist further stated that in South Sudan, papaya farmers struggled to manage mealybug infestations despite heavy reliance on pesticides.
However, CABI, in partnership with the University of Juba and NKM, brought hope through biocontrol interventions in Central Equatoria.
Miller, pushing for sustainable regional solutions noted that across East Africa, papaya mealybug threatens not only a key cash crop but also broader food security and biodiversity.
She said that CABI’s coordinated approach of combining science, farmer engagement, gender inclusivity, and cross-border collaboration, was proving that sustainable solutions are within reach.
“With Acerophagus papaya establishing itself as a powerful ally, smallholder farmers in Kenya, Uganda, and South Sudan are beginning to turn the tide against one of the region’s most destructive invasive pests, ’’ she said.