Mango Farmers’ Sweet Victory over Fruit Fly Menace

Originally published on June 2, 2015.

Daniel Kirai was a frustrated farmer. While he invested significantly in ensuring good produce from his mango orchard in Meru County, the smallholder farmer’s time and effort would seemingly amount to nothing. This was the result of fruit fly infestations which would destroy his crop leaving him with virtually nothing to sell.

“I had my best harvest in 2013, but only sold 50% due to fruit fly damage,” he explains.

Indeed, mango, a key horticultural crop, is most susceptible to fruit fly infestation with staggering losses of up to 80% as a result of the pest. Fruit-farming has a major potential impact on development through improved livelihoods as well as nutrition. But this is only if the produce is spared waste and losses resulting from pests on the farm at a minimum.

Unknown to Daniel and other mango farmers in the area, help was on the way!

A variation of Real IPM's fungus auto-dissemination device in use in a mango orchard in Meru. The fungus kills fruit flies.
In February 2014, Real IPM (Kenya) Ltd was among the first cohort of innovators under the USAID-funded Kenya Feed the Future Innovation Engine program. Launched in 2012, the five-year program identifies, fosters, and brings to scale innovative market-driven solutions to persistent food insecurity, under nutrition and poverty.

In the subsequent months, Daniel Kirai would become one of more than 100 farmers that Real IPM would train on the use of their innovation - a fungus which kills fruit fly. Together with the International Centre of Insect Physiology and Ecology (ICIPE), Real IPM has been working to test the fungus (Metarhizium anisopliae 69) for the biological control of the fruit fly. The fungus is applied to the soil and is also sprayed on the leaves of the crop. Specially-designed devices which attract the fruit flies and attach the fungus to them make the innovation unique, as the insects literally take part in disseminating the fungus thereby killing off more fruit flies.

In early 2015, almost exactly one year after the project began working with mango farmers, Daniel Kirai can attest to the benefits of the innovation.

“When Real IPM came in 2014, they introduced me to their innovation and taught me how to manage the fruit fly menace. This season, I have sold 90% of my produce," Daniel said. “The fruit that I could not sell was not damaged by fruit fly, but rather by physical damage when it fell from the tree," he explains.

Henry Ngari, a mango farmer based in Embu is also thrilled at the opportunities that the innovation presents.

Mango farmer Henry Ngari tells of the success he had controlling fruit flies using the Real IPM system
“I have lost 100% of my mangoes to the fruit fly in some years. But now, I am back in business thanks to the Real IPM innovation," Henry says. "With a combination of the soil drenches and the auto-dissemination devices, I have achieved about 90% control. The middleman who sells my mangoes to shops in Nairobi was so happy with the produce that he told his customers that he would give them KSh. 100 for each mango they found with a fruit fly in it!” Henry adds excitedly.

This is significant in light of the huge lost opportunity to market the fruit internationally, given that conventional fruit fly control methods do not adequately manage the risk of contamination of fruit exports. This has led many countries to ban fresh mango exports from East African countries, citing the presence of the exotic fruit fly.  

The results of separate efficacy trials by Real IPM and the University of Nairobi corroborate Daniel and Henry’s testimonies; the trials, completed in early 2015, demonstrated that Metarhizium 69 is an effective biological control option for all species of the fruit fly.

In March 2015, Daniel, Henry and more than 180 other mango farmers in Meru, Embu, Machakos, and Makueni Counties who are also working with the innovation were more than happy to participate in open days where Real IPM presented these results to farmers. This group forms the initial target customers for the product.

Farmers testing the innovation confirm that there is a drastic reduction in all species of mango fruit fly infestation. On average, fruit fly infestation reduced by around 40% while mango seed weevil infestation was also reduced by around 30%. Farmers testing the innovation have also noted that use of the fungus significantly reduced their labor and crop protection budgets.

So far, Real IPM has developed the auto-dissemination devices using locally-available materials in the focus counties and made significant progress in the production and packaging of the fruit-fly killing fungus. The commercialized fungus will be available to smallholder farmers through agrovets and other local distributors, on approval from Pest Control Product Board. It is anticipated that the technology will eventually contribute to the lifting of export restrictions once fruit fly control is exhibited on a national scale.

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