The papaya mealybug is a serious pest of the fruit, which originated from Central America before spreading to the Caribbean and South America in the 1990s. Heavy infestations cause stunting, leaf yellowing, leaf curl and early fruit drop. Fruits and stems may be completely covered by a white layer of mealybugs and wax secretions. Affected fruits’ tissue underneath the mealybug colonies becomes hard and bitter.
“More than half of Kenya has been invaded by the papaya mealybug and its impact has led to some farmers abandoning growing the fruit altogether,” said Mr Fernadis Makale, an Invasive Species Management Assistant based at CABI’s Kenya centre in Nairobi. He is part of a team of CABI (Centre for Agriculture and Bioscience International).
To enhance control of this devastating pest, researchers from CABI shared their expertise on the pest’s management, as part of a new multiagency technical brief addressing the description, identification and its sustainable management.
The brief contains the latest advice for papaya mealybug management. It will support the development of a range of information materials for extension workers, agro-dealers, and farmers.
A technical team from a range of partners has reviewed the document. It included representatives from the Ministries of Agriculture, Livestock, Fisheries and Industry, Trade and Cooperatives, Mombasa, Kilifi and Kwale county governments. Others are the Kenya Agricultural & Livestock Research Organisation (Kalro), Kenya Forestry Research Institute (Kefri), Kenya Plant Health Inspectorate Service (Kephis), National Museums of Kenya, the University of Nairobi and Precision Agriculture for Development.
“The technical brief is the culmination of shared expertise across many partners, with the same aim of tackling this devastating pest of the papaya fruit – a key crop for many smallholder farmers in Kenya who rely on it to sustain their livelihoods,” said Dr Monica Kansiime, a scientist and agricultural economist at CABI’s centre in Nairobi,.
“It also stems from multi-stakeholder workshops, co-financed by Darwin Initiative-funded Project “Biodiversity and Agriculture: Addressing Scale insect threats in Kenya”, the CABI-led Plantwise, and CABI’s Action on Invasive programmes, where we reviewed the evidence of the impact of the papaya mealybug, and how to best communicate the risks and Integrated Pest Management (IPM) techniques to papaya farmers,” Dr Kansiime added.
In 2017, SciDev.Net reported how pawpaw farmers in Pakistan averted a near-complete devastation of the country’s papaya crop, which was affected by the mealybug pest, after replacing ineffective conventional chemical pesticides with natural predators that proved to be successful.
The intervention was made possible through CABI’s papaya pest management programme, which involved researchers setting up the Natural Enemies Field Reservoirs on farmers’ fields to breed the Acerophagus papaya parasitoid as well as eight other natural predators of the mealybug.Mr Joshua Oluyali, head horticulturist in the Ministry of Agriculture, Livestock, Fisheries and Cooperatives, said the government appreciates the work done by CABI and will provide the necessary support for the management of the pest in pawpaws to stop the spread and reduce losses caused by the pest.