Nairobi: A nature-based solution is demonstrating outcomes in supporting farmers in Kenya, Uganda, and South Sudan and sustainably revitalising their papaya (pawpaw) crops affected by papaya mealybug pest. The papaya mealybug, known scientifically as Paracoccus marginatus, is a pest wreaking havoc across East Africa, slashing yields, reducing orchard lifespans, and undermining food security and livelihoods.
According to News Agency of Nigeria, Dr. Selpha Miller, an Invasive Species Management expert, shared insights during an interview about the classical biological control strategy for papaya mealybug using the parasitic wasp, Acerophagus papaya. She noted that Nigeria is also affected by the pest. The interview took place during a visit to the Crop Protection Biological Control Laboratory in Kenya, as a pre-tour of the World Congress of Agricultural Journalists event scheduled for Oct. 15 to Oct. 18 in Nairobi, Kenya.
Dr. Miller emphasized the significance of papaya as a staple fruit in East Africa, serving both as food and a cash crop. She revealed that the pest originated in Central America, was first detected in Africa in 2010, reached Kenya in 2016, and Uganda in 2021. The crop losses, valued at around 2,223 pounds per hectare annually, have been devastating.
Kenya, in partnership with CABI, a centennial non-profit organization, began deploying the parasitic wasp to control pests in coastal and inland areas. When other methods failed, the parasitoid emerged as the most effective method to control invasive pests. Mass release of the parasitoid commenced in December 2021, with 1,822,625 parasitoid individuals supplied to 990 farmers in nine countries. A total of 3,679 farmers across these countries have been trained and sensitized about papaya mealybug control using Acerophagus papaya parasitoid. The project has also enhanced the capacity of 260 extension officers and 29 crop inspectors in the countries on papaya mealybug biocontrol.
The CABI scientist highlighted that the parasitoid has successfully established in Kenya’s coastal region, achieving over 70 percent parasitism. Within a year, papaya production recovered to levels before the mealybug invasion. Following pesticide withdrawal by participating farmers, a high number of predators and previously absent natural enemies were observed at release sites.
A full socioeconomic assessment of the project, conducted in March and following a 2019 baseline, indicated that the biological intervention increased papaya yields and income by 19 and 57 percent, respectively. Dr. Miller stated that the papaya mealybug threatened a key cash crop, food security, and biodiversity. CABI’s coordinated approach, combining science, farmer engagement, gender inclusivity, and cross-border collaboration, is proving that sustainable solutions are attainable.
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.