He who laughs last...

“It was a huge problem,” recalls James Gichovi from Kimangaru (Kenya); he is referring to the swarm of fruit flies that descended on his mangos. “They were absolutely everywhere – we had no chance” Eventually, he found a way to protect his mangos in a sustainable way.

Peter Lüthi, Communication

Mango farmer James Gichovi

  • James Gichovi has good reasons to laugh because his mangoes are now safe from the fruit flies: Here with one of his homemade fly traps.
  • Initially, he experimented on his own and only achieved a real breakthrough at an IPM Field Day run by icipe, where one of the recommendations was the use of mesh tents.
  • Samira Mohamed and her colleagues from icipe recommend “Integrated Pest Management” to the Kenyan mango farmers.
  • James Gichovi’s trees are laden with mangoes. The fruit are no longer under attack and so provide a good income for farmers and their families.

Mr Gichovi had been spraying large amounts of chemical pesticides but in the end, they too failed to work. He then discovered that you could control the fruit flies with traps and odour bait. In reality, this was just one of a range of measures in a system called “Integrated Pest Management” (IPM). As part of the IPM method, parasitic wasps are released, and they attack the larvae and decimate the population. The fruit that falls to the ground is collected on a regular basis and placed in special mesh tents; the fruit flies and larvae remain trapped in the tents whereas the smaller parasitic wasps are able to escape and continue to torment the young flies. Odour traps are also used to attract the male flies and farmers spot spray the trees with biopesticides. Finally, fungal spores are used to kill off the larvae in the soil.

“Integrated Pest Management” in practice

  • The mangoes infested with fruit fly larvae are collected in small-mesh nets from which the beneficial insects (wasps) can escape but the larger fruit flies cannot.
  • The parasitic wasps, affectionately called “Farmers Friends” by mango farmers, are released into the mango groves. There they attack the fruit-fly offspring and so reduce the pest population.
  • Odour bait is used to attract the male fruit flies to the traps where they are killed with a bio-insecticide.
  • Traps for the male flies are crucial to the success of pest management
  • Here, Peterson W. Nderitu from icipe explains to a mango farmer how the so-called augmentoria (net traps for the fruit flies) work
  • Fruit flies are bred at icipe for research purposes.
  • Research at the icipe laboratory: The mangoes under the net are riddled with the eggs or larvae of the fruit fly. The parasitic wasps lay their eggs through the mesh onto the eggs or larvae.
  • The IPM methods developed by icipe are also effective against the indigenous fruit fly (ceratitis osyra).

James Gichovi initially experimented on his own and achieved some success with plastic buckets and odour bait. His final breakthrough came at an IPM Field Day run by icipe* and Biovision. Nowadays, James has the fruit fly under control and is able to protect his mangoes in a sustainable way. However, he is not totally satisfied and remains concerned: “The training was too short and the groups were too large,” laments James. Many of the participants would have failed to understand everything and that is a shame. “In order to keep the mango fruit flies in check permanently, every farmer should use the IPM method diligently and consistently. I will only stop worrying when we are doing that”. It is a good thing, therefore that Biovision and icipe are continuing with the Fruit Fly Control project.

* icipe: International Centre of Insect Physiology and Ecology