•They hope to also release it in Meru, Murang’a, Kitui, Homabay, Busia and Baringo – thereby covering all 10 of the major pawpaw growing counties in Kenya, Cabi said in a statement.
•Laboratory parasitism of 77.5 per cent, 72.5 per cent and 47.5 per cent in adult females, third and second instars respectively was obtained, Cabi said.
Image: Handout
Experts will release an enemy insect to fight the devastating papaya mealybug, which is destroying pawpaws across Kenya.
Investation by the mealybug can destroy half of all pawpaw fruits in a plantation and create a thick layer of pests themselves and white wax, which makes the fruit inedible.
The enemy insect, called Acerophagus papayae(A. papayae) is a small parasitic wasp. It does not affect the fruit but only attacks the papaya mealybug by laying eggs on the pest until it dies.
A. Papayae will be deployed in Machakos, Makueni, Tharaka Nthi and Embu counties.
The wasp will be deployed by experts from Cabi, the Kenya Agricultural and Livestock Research Organisation (Kalro), the National Museums of Kenya and Kenya Plant Health Inspectorate Services (Kephis).
They hope to also release it in Meru, Murang’a, Kitui, Homabay, Busia and Baringo – thereby covering all 10 of the major pawpaw growing counties in Kenya, Cabi said in a statement.
Papaya mealybug originated from Central America before spreading to the Caribbean and South America in the 1990s. The pest was first detected in Africa in 2010 in Ghana and in Mombasa County, in 2016.
“Cabi researchers found that more than half of Kenya has been invaded by papaya mealybug and its impact has led some papaya farmers abandoning farming the fruit altogether, the Nairobi-based NGO said in a statement.
"Cabi, Karlo and Kephis have seen crop losses ranging from 53-100 per cent.”
It said A. papayae helps reduce the over-reliance on more harmful pesticides.
Mealybugs resist most of these pesticides as their waxy secretions insulate them against chemicals.
Before the release, the performance of A. papayae had been evaluated under laboratory conditions for its efficiency as a potential agent for use.
Laboratory parasitism of 77.5 per cent, 72.5 per cent and 47.5 per cent in adult females, third and second instars respectively was obtained, Cabi said.
Consequently, a dossier on the laboratory performance of the parasitoid and formal application for field release was presented to the Kenya Standing Committee on Imports and Exports for consideration before approval was granted.
,“The papaya mealybug is a significant pest that can devastate a whole crop if left unmanaged. This not only has a severe impact on the livelihood of a smallholder farmer but also the ability to contribute to local, national and global food security," Dr Ivan Rwomushana, senior scientist at Cabi, said
“It is hoped that following the releases of A. papayae, Natural Enemies Field Reservoir (NERF) technology, pioneered by the late Cabi scientist Riaz Mahmood in Pakistan, will also prove fruitful in mass-rearing the parasitoid against papaya mealybug in Kenya.”
Under the release programme for A. papayae, Cabi is working with Kephis and KALRO to increase awareness about the classical biocontrol of papaya mealybug and build the capacity of farmers, extension officers, researchers, input suppliers and policymakers to manage the pest.
The organisation said it is also training and helping farmers to establish NEFRs in farmers’ fields that would act as a natural home for the Acerophagus papayae parasitoid the farmers’ fields and help in the conservation of the parasitoids in communities when the project ends.