A trader sorts out mangoes at Daraja Mbili market in Kisii County on 21/1/2021. [Sammy Omingo, Standard]

Every season since 1990, Gideon Wambua, 62, a seasoned mango farmer from Kalamba, Makueni County, was enjoying proceeds from his family farm until 2010.

Wambua, a father of five, was a hotelier in Mombasa. However, he decided to pack and return to his native home to soil his hands for a living.

Today, he owns 4 acres of land filled with 250 mango trees.

“I quit the job and started mango farming. It was well paying although we used to sell to brokers by that time,” Wambua says

However, in 2010 things changed for the worst. This was after mango farmers in Makueni started experiencing huge post-harvest losses due to the fruit fly. The new fruit fly species from the Bactrocera dorsalis (Hedel) group from Sri Lanka was detected in Kenya in 2003 through the coastal region.

“The yields were good from 1990 but after 2010, the production went down following the attacks on our crops. Most of the fruits were seen with a ripening colour which was false. They would later start rotting and eventually fall after getting punctured by the flies which at the time we didn’t understand well,” he added

He adds: “The yields went down and at some point mango farmers decided to cut down their trees. The pests affected the crops adversely. In 2019, I only managed to sell 12 tonnes. In 2020, I collected 15 tonnes. This increase can be attributed to the introduction and adoption of technologies promoted under the Komesha Fruit Fly Campaign to eradicate fruit flies in Makueni.”



He estimates producing 25 tons in 2021 with a commercial market price of Sh25 per piece which will translate to Sh1.8 million out of the current stock.

In January 2020, the Kenya Crops and Dairy Market Systems Activity (KCDMS) and the United States Agency for International Development (USAID) in collaboration with the County Government of Makueni and other partners such as the Rockefeller Foundation’s Food Initiative, the Kenya Plant Health Inspectorate Services (KEPHIS) and the Horticultural Crops Directorate (HCD) launched the Komesha Fruit Fly Campaign to create pest-free zones.

The USAID- KCDMS project formed the Mango Technical Working Group to bring together key stakeholders from the agriculture sector, the government, the private sector and mobilised the resources needed to eliminate the fruit fly and to once again resume exports to the EU and other lucrative markets.

Hellen Heya is an entomologist with KEPHIS. She explains that due to the fruit fly infestation on Kenyan mangoes, the inspectorate was forced to impose a ban on exporting mangoes to the European Union markets in 2014.

“The high levels of the fruit flies in the shipments forced us to stop exporting to these markets. The oriental fruit flies had become so destructive and we had to stop exporting and work on ways of create areas of low pest prevalence before resuming,” she disclosed



Before the introduction of the integrated pests management (IPM) technologies through the Komesha Fruit Fly Campaign, small-scale farmers like Miriam Kanini from Kilili Village in Makueni turned into the application of synthetic pesticides with the fruit flies becoming resistant to the chemicals.

“Before the campaigns, we used to spray the plants with chemicals. This was not only an expensive process but also would kill any predators preying on these flies hence their multiplication instead of killing them,” said Kanini

In 2018 and 2019, Kanini harvested half-ton and 1 ton, respectively. However, in 2020, she managed 2 tonnes of mangoes, thanks to the Komesha Fruit Fly Campaign.

“I plant mangoes in an acre. I can report that due to the campaign which has employed the use of agricultural extension officers to educate us on how to trap the pest. The produce is better,” Kanini says.

To eradicate the menace, KCDMS project co-invested with Integrated Pest Management (IPM) technology providers, including  Farmtrack Consulting Ltd, Real IPM, Faina Innovations Ltd, Kenya Biologics, and Ifarm Konnect to offer these technologies to mango farmers.

Simon Mbai, a pest control expert from Farmtrack, underscores the importance of using physical pest control methods as compared to other methods of biological and cultural.

“We use locally available containers which are fitted with wire attached to a bactrolure bait that contains pheromone (Male annihilation technique- MAT), which is a hormone that attracts and kills the male fruit flies,” says Mbai

According to the expert, pheromones are hormones that induce sexual arousal among male fruit flies. The male fruit flies will be attracted into the traps to mate only to be trapped, and they die.

“We target the male fruit flies to stop their production. The female fruit flies will at the end lack fertilization of their eggs, lay them prematurely and the generation is discontinued. This is how we crash the population,” he reveals of the farm Track technology.

This must be a universal action done by all farmers lest the fruit flies from the neighbors will spread to other farms. In this regard, the farmers have joined various co-operatives for easy control of the pest.

A farmer mounts 4 traps per acre and one trap is effective for a period of 2 months before changing the bait.

Timothy Mwangi, an agronomist with KCDMS emphasises the need for maintaining farm sanitation while fighting mango diseases.