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How to improve the value of African mango and cashew production?

Weaver ants have proven to be efficient as pest control agents in mango and cashew plantations, where they can double the yield and have been shown to be more cost effective than pesticides. Studies of value chains, export barriers and European markets for organic products have shown that there is a great potential for improving the monetary output from the increased production. The mango value chain does not include export and hardly any local processing is involved. One of the biggest obstacles for mango exports to Europe is the quality requirement, as damage from fruit flies is not accepted. Regarding cashew nuts, there is a great export of raw nuts to India, where processing takes place. Therefore, there is a great potential in initiating local processing of both cashew nuts and mango for both local consumption and export in Tanzania and Benin, and there is a virtually untapped market for organic production of these fruits in Denmark and Germany.

In 2015, the Danida funded project ”How to improve the value of African mango and cashew production” was completed. Thus, we are now able to write about the results of the project. The aim of the project was to reduce poverty, create jobs and increase African export earnings. In order to do this, the project developed and implemented an efficient and ecologically sustainable production of cashew and mango, using ants for pest control. Under this general objective, we had six specific objectives:

  1. To introduce, develop and optimize Integrated Pest Management (IPM) using weaver ants in cashew and mango in Benin and Tanzania and using these countries as a stepping stone to other African countries south of Sahara
  2. To develop agribusiness by increasing the yield and quality (and allow organic certification) of cashew and mango and stabilizing production in order to facilitate exports
  3. To establish ties between farmers, processing plants, organic certification bodies and European retailers with the aim of strengthening value chains and access to export
  4. To increase African smallholders’ access to protein by introducing Southeast Asian techniques for harvesting weaver ant queens for consumption and/or export
  5. To implement pest control using weaver ants by educating extension workers and farmers and by preparing learning material and manuals
  6. To build research capacity (Ph.D. program) at university level in order to further develop sustainable production methods.

Here, the results of the project are discussed in relation to the above-mentioned specific objectives:

  1. Sixteen scientific articles have been published about weaver ants in relation to pest control in mango and cashew, and the results have clearly paved the way to introducing and optimizing weaver ants as part of the IPM-program in mango and cashew plantations in Tanzania and Benin. Although the results are only from two countries, it is highly probable that the results also apply to other countries, which means that Tanzania may be a stepping stone in East Africa and Benin in West Africa.
  2. Ten scientific articles deal with increasing the yield in quantity and quality, and they mainly focus on how to improve the efficiency of weaver ants in the biological control of mango and cashew. It was demonstrated that transferring larvae and pupae from other colonies and feeding with sugar and meat may increase the efficiency of weaver ant colonies and, thus, improve both the yield and the quality of fruit/nuts. This is done without the use of pesticides and, thus, enables organic farming.
  3. A scientific article, a chapter from a Ph.D. thesis, and not yet published material discuss commercial sales of the improved harvest of mango and cashew. They identify export barriers that prospective exporters from Benin and Tanzania are facing.
    Mango exports from Benin and Tanzania to Europe are very limited, and there is virtually no local processing of fruit. Local processing faces logistical challenges due to poor infrastructure (lack of cooling facilities, lack of refrigerated vehicles and poor roads) and high transportation costs due to lack of competition in container shipping from Africa to Europe. Cashew nuts are hardly processed locally in Tanzania or Benin, as most nuts are sent to India for processing. This is difficult to change, as the Indian buyers weigh heavily on the market.
    Overall, European importers require that the production meets European food safety standards – both regulatory requirements and private standards, such as BRC or Global G.A.P. Many African countries lack bodies that can support certification and monitoring compliance with these requirements. This makes it difficult for African companies to export to Europe.
  4. However, the concept of harvesting weaver ant queens as a food source had to be abandoned, as the African weaver ant does not have a specific peak time for producing queens. Rather, they virtually produce queens year round. For this reason, it did not make sense to harvest queens using the Southeast Asian method, as the yield of queens and larvae was not worth the effort.
  5. The methods developed in the project are described in detail in the photo-book “Cashew and Mango Integrated Pest Management Using Weaver Ants as a Key Element For organic cashew and mango growers in Africa”, published by Rengkang Peng, University of Darwin. The photo-book is a very important product of the project, and the African partners have received electronic versions for distribution.
    A training course for farmers and agricultural advisors was held in Tanzania, and a documentary on weaver ant technology was broadcast by Tanzania Broadcasting.
  6. Capacity building took place via the Ph.D. program, in which 4 students from Tanzania and 3 students from Benin conducted their research and graduated in 2015 and early 2016. All students spent 6 weeks at Aarhus University in Denmark, and in 2012 they participated in courses on biological pest control, statistics and scientific writing. In 2013, they mainly received training in practical data-analysis, and in 2014 they focused on preparing scientific articles based on their data. This was done in close collaboration with the Danish supervisors. The Ph.D. students were further trained in handling weaver ants in the field and in conducting statistical experiments.