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Socio-economic and modelling studies of cocoa pests and diseases


United States Department of Agriculture (USDA)


Imperial College (UK)

Project Description

Problem/Issue. Insect pests and diseases limit the production and profitabilty of cocoa production in many countries. There are a number of difficulties associated with the effective management of these pests that are difficult to evaluate purely from field experimentation. These relate to the time and cost necessary to collect field data for the many possible combinations of potential management strategies available to farmers. Computer simulation models can be used to combine available knowledge in a biologically and economically cohesive way so that management strategies can be evaluated in terms of the in-field suppression of the pest and the economic return that the strategy provides. The resulting models may be used to test "what-if?" scenarios for policy strategists and provide training for extensionists by giving them access to virtual "plantations" where their ideas may be tested dynamically under a range of user-definable, realistic economic and environmental conditions.

Measures to Date. A preliminary model of Moniliophthora sp. in Costa Rica has led to considerable interest from the primary buyer of Costa Rican cocoa. They have expressed interest in using the model to train extension and in-house staff in the dynamics of the disease and the economics of its management. They currently pay a premium for Cost Rican cocoa because of its organic status, however, at higher international cocoa prices the current level of premium would not be sustainable. This presents a concern not only to the company but also to those farmers whose market would be lost if the company was to reduce its acqusition because of unsustainable cost increases. The model would allow company strategists to evaluate how different premium levels might affect their own economics as well as the price that farmers receive leading to greater sustainability of production and acquisition. The model may also provide value when applied to other diseases such as Phytophthora sp. which causes considerable losses in West Africa as well as South East Asia, and Central & South America. The current Monilia model is capable of being used in any country that has the disease and we are looking to adapt the model for South American countries.

Project Activities. CABI Commodities has considerable expertise in many aspects of cocoa work (see other projects) while Imperial College has extensive expertise in computer simulation models that can be used to combine available knowledge in a biologically and economically cohesive way to test management strategies.

Achievements So Far

This is the first attempt to build a simulation model of monilia that includes the crop phenology, disease dynamics and economics from a farmer management viewpoint. The value of this approach is that the bottom-up approach yields useful insights for farmers extensionist, buyers and policy strategists.

What Next

Initial model development has shown that there is considerable interest in this model from buyers. The model however has relied on some assumptions based on perceptions of key experts in the field rather than actual field data. This situation needs to be improved by gathering data describing the disease's epidemiology and ecology within the field. The model will also be adapted for other countries within Central and South America. It is hoped that other diseases may also be entered into the model with only small adjustments to the current coding.

Dr. John Mumford (Co-ordinator) j.mumford@ic.ac.uk
Dr. Adrian Leach a.w.leach@ic.ac.uk

Start date: February 2000

End date: March 2001


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Contact CABI Commodities:
CABI Commodities Coffee Co-ordinator - Dr. Peter Baker - p.baker@cabi.org
CABI Commodities Cocoa Co-ordinator - Dr. Keith Holmes - k.holmes@cabi.org
CABI Commodities Project Administrator - cabi-commodities@cabi.org